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    P2437 Secondary Air Injection System Air Flow/Pressure Sensor Circuit Low Bank 2

    What does this OBD II code mean? 

    This generic OBD2 code is set when the Powertrain Control Module (PCM) senses a voltage lower than expected in the Secondary Air Injection System (AIR) pressure sensor circuit.
    This particular code is pointing out the bank 2, in other words, the bank of cylinders not containing cylinder #1.

    Why does this OBD II code appear?

    The objective of the Secondary Air Injection System (AIR) is decreasing the hydrocarbon emissions under certain conditions. In order to accomplish that goal AIR inject fresh air to the exhaust system using an air pump. Besides the air pump, the AIR system uses one or more actuators (valves or solenoids) to divert the air stream as well as a pressure sensor.
    The OBD2 code P2437 is stored in memory when the PCM detects an AIR pressure sensor voltage lower than the acceptable limit.

    What symptoms may occur with this OBD II code?

    Expect the typical symptoms from a P2437 condition:

    • CEL lit. The Check Engine Light will turn on after few driving cycles to alert the driver about the situation. 
    • The engine may die during idle.
    • Possible hesitation during idle or while accelerating.
    • Possible noise from the AIR system.

    What are the causes that trigger this OBD II code?

    There're many factors that could cause a P2437 condition including among others the following:

    • Damaged, burnt, corroded, open or shorted AIR pressure sensor. 
    • Worn, corroded, burnt, disconnected or bent AIR pressure sensor wiring harness connector pins. 
    • Faulty or deficient AIR pressure sensor.
    • Faulty or deficient AIR solenoids.
    • Faulty or deficient air pump.
    • Even when unlikely, a defective PCM cannot be discarded.

    Diagnostic strategy for troubleshooting this OBD II code

    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 P2437 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 P2437 is as follows:

    1. Sensor harness wiring and connector: carry out an exhaustive visual inspection of AIR pressure 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.
    2. 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 AIR pressure sensor. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature. 
    3. AIR pressure sensor: using a scan tool you can check the sensor output. With the help of a manual vacuum pump perform a KOEO test to check its condition. Replace as necessary.
    4. AIR system functional test: some manufacturers include built-in tests that help in the process of diagnosing the AIR system, others not. Refer to the proper literature in order to perform a complete system diagnostic. The test allows you to manipulate the solenoids and air pump activation. Replace if needed.
    5. 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.
       

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