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What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a short circuit between the O2 sensor signal and the heater element circuit. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 3 tag is indicating the downstream O2 sensor located just after the last catalytic converter. Why does this OBD II code appear? Most of these oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that its no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short. The OBD2 code P2233 is stored in memory when the PCM detects a short in the sensor signal with the heater element circuit for bank 1, sensor 3. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2233 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2233 including among others the following: Damaged, burnt, corroded, open or shorted downstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent downstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2233 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2233 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 downstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Heater circuit relay/fuse: on systems with a positively controlled heater circuit is not uncommon to find a relay and/or fuse as part of the circuit. Check its condition and replace as necessary. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 downstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Downstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a short circuit between the O2 sensor signal and the heater element circuit. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just after the catalytic converter. Why does this OBD II code appear? Most of these oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that its no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short. The OBD2 code P2234 is stored in memory when the PCM detects a short in the sensor signal with the heater element circuit for bank 2, sensor 1. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2234 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2234 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2234 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2234 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Heater circuit relay/fuse: on systems with a positively controlled heater circuit is not uncommon to find a relay and/or fuse as part of the circuit. Check its condition and replace as necessary. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a short circuit between the O2 sensor signal and the heater element circuit. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 2 tag is indicating the downstream O2 sensor located just after the catalytic converter. Why does this OBD II code appear? Most of these oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that its no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short. The OBD2 code P2235 is stored in memory when the PCM detects a short in the sensor signal with the heater element circuit for bank 2, sensor 2. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2235 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2235 including among others the following: Damaged, burnt, corroded, open or shorted downstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent downstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2235 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2235 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 downstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Heater circuit relay/fuse: on systems with a positively controlled heater circuit is not uncommon to find a relay and/or fuse as part of the circuit. Check its condition and replace as necessary. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 downstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Downstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is open. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2238 is stored in memory when the PCM detects a voltage lower than the expected in the positive circuit line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2238 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2238 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2238 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2238 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is shorted. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2239 is stored in memory when the PCM detects a shorted circuit in the positive line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2239 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2239 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2239 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2239 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is open. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2240 is stored in memory when the PCM detects an open circuit in the positive line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2240 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2240 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2240 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2240 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is open. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2241 is stored in memory when the PCM detects a voltage lower than the expected in the positive circuit line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2241 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2241 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2241 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2241 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is shorted. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2242 is stored in memory when the PCM detects a shorted circuit in the positive line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2242 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2242 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2242 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2242 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses an open ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2251 is stored in memory when the PCM detects an open circuit in the ground line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2251 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2251 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2251 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2251 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses an open ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2252 is stored in memory when the PCM detects a voltage lower than the expected in the ground circuit line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2252 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2252 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2252 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2252 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a shorted ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2253 is stored in memory when the PCM detects a voltage higher than the expected in the ground circuit line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2253 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2253 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2253 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2253 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses an open ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2254 is stored in memory when the PCM detects an open circuit in the ground line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2254 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2254 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2254 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2254 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses an open ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2255 is stored in memory when the PCM detects a voltage lower than the expected in the ground circuit line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2255 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2255 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2255 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2255 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a shorted ground circuit in the upstream oxygen sensor. This particular code is pointing out the bank 2, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2256 is stored in memory when the PCM detects a voltage higher than the expected in the ground circuit line used for control. Depending on the sensor design the ground line may be shared between the heater circuit and the sensor data circuit. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2256 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2256 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2256 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2256 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 2 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 2 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) constantly senses a rich mixture with little or no change over time. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 3 tag is indicating the downstream O2 sensor located just after the last catalytic converter. Why does this OBD II code appear? Post catalyst oxygen sensors normally cycle between rich and lean mixtures at a slow rate. Their waveform is somewhat flat but the value is never constant. When the PCM detects a bias toward a rich state or worse yet, a fixed value close to 0.9V, it initiates the compensation protocol and turns on the CEL. The OBD2 code P2275 is stored in memory when the PCM detects a condition like the explained above where the bank 1, sensor 3 is constantly reporting a rich mixture during a given period of time, even after fuel delivery compensation. What symptoms may occur with this OBD II code? Assuming a rich mixture is indeed present, expect the typical symptoms from such condition: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy. Possible misfires and/or spark knock. You may have rough idling. Possible hesitation during acceleration. A strong gasoline smell on the exhaust and/or a “rotten eggs” smell. Depending on the vehicle year a slight rise in engine temperature may occur. Under extreme circumstances, a black smoke may be noticeable coming out the exhaust pipe. What are the causes that trigger this OBD II code? There're many factors that could cause a rich mixture condition including among others the following: Damaged, burnt, corroded, open or shorted O2 sensor wiring. Worn, corroded, burnt, disconnected or bent O2 wiring harness connector pins. High fuel system pressure caused by the fuel pump or faulty/deficient fuel pressure regulator Excess fuel caused by stuck fuel injectors or even dirty fuel injectors not pulverizing fuel as expected (deficient fuel spray). Faulty or deficient upstream oxygen sensor. Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Please notice that possible causes are based on the assumption that only trouble code P2275 is stored in memory. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related to the bank 1 oxygen sensor 1 is present then you must start diagnosing and solving those codes first. The same recommendation applies to MAF sensor trouble codes. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2275 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2275 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of MAF sensor and oxygen sensor wiring and connectors. Pay special attention to burnt, corroded or deteriorated wiring and/or connector. Unplug each sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO check on the MAF and O2 sensors. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. Fuel system delivery: carry out a manual fuel pressure reading using a proper fuel pressure gauge and adapters. This is crucial, even if the scanner is reporting the fuel pressure. If the fuel pressure is above its normal value then perform an extensible fuel system test starting with the fuel pump followed by the fuel pressure regulator and fuel injectors performance. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Downstream oxygen sensor: most vehicle manufacturers use traditional oxygen sensors (instead of A/F sensors) for the post-catalyst monitoring. This opens you the possibility of performing the sensor test using a DVOM, an oscilloscope or a scan tool. Refer to the proper OEM literature in order to decide what is the best approach. Replace the O2 sensor if necessary and repeat all KOER tests before continuing. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a short circuit between the O2 sensor signal and the heater element circuit. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just after the catalytic converter. Why does this OBD II code appear? Most of these oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that its no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short. The OBD2 code P2231 is stored in memory when the PCM detects a short in the sensor signal with the heater element circuit for bank 1, sensor 1. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2231 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2231 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2231 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2231 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Heater circuit relay/fuse: on systems with a positively controlled heater circuit is not uncommon to find a relay and/or fuse as part of the circuit. Check its condition and replace as necessary. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses that the upstream oxygen sensor positive circuit is open. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 1 tag is indicating the upstream O2 sensor located just before the catalytic converter. Why does this OBD II code appear? Most of the oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that it's no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short or open circuit. The OBD2 code P2237 is stored in memory when the PCM detects an open circuit in the positive line used for control. Depending on the year of the vehicle, manufacturer and the sensor design the positive line may have a relay and a fuse. Those elements may also trigger this code. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2237 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy Possible misfires, spark knocking or detonations. Possible rough idle and/or engine hesitation. Sometimes you may expect a lack of power, especially during hard acceleration. In general, expect any condition directly related to an incorrect air-fuel mixture. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2237 including among others the following: Damaged, burnt, corroded, open or shorted upstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent upstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient upstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2237 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2237 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 upstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 upstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Heater Circuit Relay and Fuse: on some vehicles, you may find a relay that is controlled by the PCM to operate the heater element circuit. If that’s the case, check the condition of the relay and its fuse. Replace as necessary. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) constantly senses a rich mixture with little or no change over time. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 2 tag is indicating the downstream O2 sensor located just after the catalytic converter. Why does this OBD II code appear? Post catalyst oxygen sensors normally cycle between rich and lean mixtures at a slow rate. Their waveform is somewhat flat but the value is never constant. When the PCM detects a bias toward a rich state or worse yet, a fixed value close to 0.9V, it initiates the compensation protocol and turns on the CEL. The OBD2 code P2271 is stored in memory when the PCM detects a condition like the explained above where the bank 1, sensor 2 is constantly reporting a rich mixture during a given period of time, even after fuel delivery compensation. What symptoms may occur with this OBD II code? Assuming a rich mixture is indeed present, expect the typical symptoms from such condition: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy. Possible misfires and/or spark knock. You may have rough idling. Possible hesitation during acceleration. A strong gasoline smell on the exhaust and/or a “rotten eggs” smell. Depending on the vehicle year a slight rise in engine temperature may occur. Under extreme circumstances, a black smoke may be noticeable coming out the exhaust pipe. What are the causes that trigger this OBD II code? There're many factors that could cause a rich mixture condition including among others the following: Damaged, burnt, corroded, open or shorted O2 sensor wiring. Worn, corroded, burnt, disconnected or bent O2 wiring harness connector pins. High fuel system pressure caused by the fuel pump or faulty/deficient fuel pressure regulator Excess fuel caused by stuck fuel injectors or even dirty fuel injectors not pulverizing fuel as expected (deficient fuel spray). Faulty or deficient upstream oxygen sensor. Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Please notice that possible causes are based on the assumption that only trouble code P2271 is stored in memory. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related to the bank 1 oxygen sensor 1 is present then you must start diagnosing and solving those codes first. The same recommendation applies to MAF sensor trouble codes. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2271 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2271 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of MAF sensor and oxygen sensor wiring and connectors. Pay special attention to burnt, corroded or deteriorated wiring and/or connector. Unplug each sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO check on the MAF and O2 sensors. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. Fuel system delivery: carry out a manual fuel pressure reading using a proper fuel pressure gauge and adapters. This is crucial, even if the scanner is reporting the fuel pressure. If the fuel pressure is above its normal value then perform an extensive fuel system test starting with the fuel pump followed by the fuel pressure regulator and fuel injectors performance. Upstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Downstream oxygen sensor: most vehicle manufacturers use traditional oxygen sensors (instead of A/F sensors) for the post-catalyst monitoring. This opens you the possibility of performing the sensor test using a DVOM, an oscilloscope or a scan tool. Refer to the proper OEM literature in order to decide what is the best approach. Replace the O2 sensor if necessary and repeat all KOER tests before continuing. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) constantly senses a rich mixture with little or no change over time. This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1. The sensor 2 tag is indicating the downstream O2 sensor located just after the catalytic converter. Why does this OBD II code appear? Post catalyst oxygen sensors normally cycle between rich and lean mixtures at a slow rate. Their waveform is somewhat flat but the value is never constant. When the PCM detects a bias toward a rich state or worse yet, a fixed value close to 0.9V, it initiates the compensation protocol and turns on the CEL. The OBD2 code P2273 is stored in memory when the PCM detects a condition like the explained above where the bank 2, sensor 2 is constantly reporting a rich mixture during a given period of time, even after fuel delivery compensation. What symptoms may occur with this OBD II code? Assuming a rich mixture is indeed present, expect the typical symptoms from such condition: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. Poor fuel economy. Possible misfires and/or spark knock. You may have rough idling. Possible hesitation during acceleration. A strong gasoline smell on the exhaust and/or a “rotten eggs” smell. Depending on the vehicle year a slight rise in engine temperature may occur. Under extreme circumstances, a black smoke may be noticeable coming out the exhaust pipe. What are the causes that trigger this OBD II code? There're many factors that could cause a rich mixture condition including among others the following: Damaged, burnt, corroded, open or shorted O2 sensor wiring. Worn, corroded, burnt, disconnected or bent O2 wiring harness connector pins. High fuel system pressure caused by the fuel pump or faulty/deficient fuel pressure regulator Excess fuel caused by stuck fuel injectors or even dirty fuel injectors not pulverizing fuel as expected (deficient fuel spray). Faulty, deficient or dirty mass air flow sensor (MAF) Faulty or deficient upstream oxygen sensor. Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Please notice that possible causes are based on the assumption that only trouble code P2273 is stored in memory. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related to the bank 2 oxygen sensor 1 is present then you must start diagnosing and solving those codes first. The same recommendation applies to MAF sensor trouble codes. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2273 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2273 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of MAF sensor and oxygen sensor wiring and connectors. Pay special attention to burnt, corroded or deteriorated wiring and/or connector. Unplug each sensor and check for corrosion, damage, bent pins, etc. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO check on the MAF and O2 sensors. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. Fuel system delivery: carry out a manual fuel pressure reading using a proper fuel pressure gauge and adapters. This is crucial, even if the scanner is reporting the fuel pressure. If the fuel pressure is above its normal value then perform an extensive fuel system test starting with the fuel pump followed by the fuel pressure regulator and fuel injectors performance. Downstream oxygen sensor: most vehicle manufacturers use traditional oxygen sensors (instead of A/F sensors) for the post-catalyst monitoring. This opens you the possibility of performing the sensor test using a DVOM, an oscilloscope or a scan tool. Refer to the proper OEM literature in order to decide what is the best approach. Replace the O2 sensor if necessary and repeat all KOER tests before continuing. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car bran

What does this OBD II code mean? This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a short circuit between the O2 sensor signal and the heater element circuit. This particular code is pointing out the bank 1, in other words, the bank of cylinders containing cylinder #1. The sensor 2 tag is indicating the downstream O2 sensor located just after the catalytic converter Why does this OBD II code appear? Most of these oxygen sensors use a 4-wire circuit, but 3-wire circuits and in some cases 5+ wire circuits are also used. What all of them have in common is the “heater circuit”. The heater element helps the sensor to reach its operating temperature faster. The PCM is constantly monitoring the heater circuit, specifically its voltage and/or current. Depending on the year and vehicle maker, the heater circuit can be commanded by the supply voltage (positively controlled) or by the ground circuit (negatively controlled). In both cases, the powertrain control module (PCM) is in charge of activating the circuit when considered necessary. Because of that, the PCM can compare in real time the heater circuit voltage (or current depending on design) with a reference value that its no other than the vehicle operating voltage. Usually, a discrepancy greater than 10% is enough to alert the PCM about a potential short. The OBD2 code P2232 is stored in memory when the PCM detects a short in the sensor signal with the heater element circuit for bank 1, sensor 2. What symptoms may occur with this OBD II code? Expect the typical symptoms from a P2232 code: CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. What are the causes that trigger this OBD II code? There're many factors that could cause a code P2232 including among others the following: Damaged, burnt, corroded, open or shorted downstream O2 sensor wiring. Worn, corroded, burnt, disconnected or bent downstream O2 wiring harness connector pins. Damaged or deficient heater circuit relay or fuse (usually only positively controlled systems) Faulty or deficient downstream oxygen sensor. Even when unlikely, a defective PCM cannot be discarded. Diagnostic strategy for troubleshooting this OBD II code Warning: If any other code directly related with the upstream oxygen sensor is present then you must start diagnosing and solving those codes first. It's highly recommended starting the diagnostic process with the usual information gathering: With the help of a professional OBD2 scan tool, preferably one with OEM capabilities, take note of all data trouble codes in memory, including pending codes. Take note of freeze frame information (if present). Query the vehicle owner about what, when and where the failure occurs. Does it happen with the engine hot? Cold? Under load? All the standard questions. Take note of the vehicle VIN and find a reliable source of technical reference. Once you are done, the next step is discarding an intermittent condition. Using your scan tool clear DTC memory. Perform a complete driving cycle according to OEM procedures. If the code P2232 disappears then inform the owner about the intermittent nature of the code and explain that further testing with the code present will be required. If the code does appear then continue to the testing stage, consisting in discarding the possible causes of the problem. IMPORTANT: the diagnostic procedure explained in this section should be taken as a guideline. Always refer to specific OEM procedures when possible. The workflow for the diagnostic process is: The tests should be executed in sequential order, in other words, complete step 1 before going to step 2 and so on. Repair, fix, or replace any component if you suspect is not in good condition. If any repair, fix, reprogramming or component replacement is made during any step then you should clear DTC memory and repeat the whole KOER driving cycle. If the DTC appear again then you should continue to the next step. If the DTC does not appear again after completing the KOER tests then you can assume the problem is fixed, in that case, continuing with the remaining steps would be optional. The diagnostic process for the code P2232 is as follows: Sensor harness wiring and connector: carry out an exhaustive visual inspection of bank 1 downstream oxygen sensor wiring and connectors. Pay special attention to burnt, corroded, open, shorted to ground or deteriorated wiring and/or connector. Unplug the sensor and check for corrosion, damage, bent pins, etc. Heater circuit relay/fuse: on systems with a positively controlled heater circuit is not uncommon to find a relay and/or fuse as part of the circuit. Check its condition and replace as necessary. Electrical tests: with the help of a digital volt-ohm meter (DVOM) and the adequate wiring diagram perform a KOEO and KOER check on the heater circuit for the bank 1 downstream O2 sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. It’s crucial during this stage to perform the adequate tests depending on circuitry design (positively controlled or negatively controlled). Downstream oxygen sensor: some manufacturers include built-in tests that help in the process of diagnosing the O2 sensor, others not. Refer to the proper literature in order to perform a complete sensor diagnostic. Replace if needed. As usual, after any repair clear the DTC memory, repeat KOER driving cycle and check if the code persists. If the code appears again then continue with the next step. Problems with the powertrain control module: the most unlikely cause for this code is a faulty PCM or a corrupted program. Yet, if you are completely certain that all prior tests passed then you must remove the PCM and check it, reprogram it or replace it as necessary. Do you need further help....? Discuss your car trouble code further with thousand's of car experts here Check your car problem in Vehicle Recall Section of your car brand