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    P2425 Exhaust Gas Recirculation Cooling Valve Control Circuit/Open

    What does this OBD II code mean? 

    This generic OBD2 code is set when the Powertrain Control Module (PCM) stops sensing the control signal from the exhaust gas recirculation (EGR) cooling valve.
    Code P2425 is only present in diesel engines equipped with EGR cooling systems.

    Why does this OBD II code appear?

    The exhaust gas recirculation (EGR) is an auxiliary emission component in charge of bypassing a small portion of exhaust gases back to the intake manifold reducing that way the dangerous NOx emissions. On diesel engines, the exhaust gases temperature is much higher than their gasoline counterparts. Depending on the engine, cooling of exhaust gases may be in order.
    Some diesel engines use a separate refrigeration system that uses the engine coolant to decreases exhaust gases temperature. Those systems use a PCM controlled valve that regulates the amount of coolant flowing through an independent radiator. Depending on input information, including but not limited to, ECT temperature and EGR temperature the PCM decide how to operate the cooling valve.
    That valve is the actuator that code P2425 is referencing to. The powertrain control module is constantly monitoring the valve circuit. If at any given time the circuit voltage is lost the code P2425 is set in memory and the CEL is lit. 

    What symptoms may occur with this OBD II code?

    The following symptoms could be present:

    • CEL lit. Due to its emissions nature, expect the Check Engine Light lit after few driving cycles.
    • In some cases, the engine may run rough. This will depend entirely on the engine coolant temperatures and PCM compensation program.
    • A possible increase in engine coolant temperature (depending on valve position).
    • Depending on the maker, year and PCM program you may encounter other EGR and ECT codes in memory.

    What are the causes that trigger this OBD II code?

    There're many factors that could cause a code P2425,  among others the following:

    • Damaged, burnt, corroded, open or shorted EGR or EGR valve wiring. 
    • Worn, corroded, burnt, disconnected or bent EGR/EGR valve wiring harness connector pins. 
    • Exhaust manifold leak. In some cases, an exhaust leak close to the EGR could burn or damage the wiring.
    • Faulty or deficient EGR cooling valve. Due to its nature, this valve is susceptible to wear. 
    • Faulty or deficient EGR valve. In some vehicles, the EGR and the cooling valve are the same part.
    • 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 EGR 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 P2425 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 P2425 is as follows:

    1. Sensor harness wiring and connector: carry out an exhaustive visual inspection of EGR and EGR valve wiring and connectors. Pay special attention to burnt, corroded or deteriorated wiring and/or connector. Unplug each connector 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 check on the EGR and EGR valve. Verify supply and/or reference voltage, electrical resistance, continuity, current and ground integrity. Compare the obtained values with the appropriate OEM literature.
    3. Exhaust manifold leak: perform a visual inspection of EGR valve looking for possible damage caused by an exhaust leak. Repair as necessary. 
    4. EGR valve functional test: using a professional OBD2 scan tool perform a functional test of the EGR cooling valve. In some cases, the best way to carry out this test is removing the EGR from the vehicle and operate the actuator under KOEO condition. This will allow you to see the valve movement or at least verify if it is opening/closing as expected.
    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.
       

     

    Do you need further help....?

    Edited by DamasoSanoja





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