СИСТЕМА ECD, Diagnostic DTC:P1401

DTC Code DTC Name
P1401 Fault Code to Indicate a Defect of EGR Cooler Bypass Valve

DESCRIPTION

In order to lower the temperature of the recirculated exhaust gas and thus further reduce nitrogen oxide emissions, the exhaust gas is recirculated through the EGR cooler assembly. With this flap, the exhaust gas is guided at low temperatures past the cooling fins into a bypass channel and thus not cooled. Only at higher engine temperatures does the ECM open the bypass flap and the exhaust gas is cooled again.

This function reduces the HC emissions in cold operating conditions. The EGR cooler bypass switching valve assembly is opened during EGR operation if the coolant temperature is lower than 50°C.

DTC No. DTC Detection Condition Trouble Area
P1401

Even though EGR cooler bypass switching valve assembly operation conditions are met, temperature does not change after passing through EGR cooler

(3 trip detection logic)

  • Vacuum system

  • EGR cooler bypass switching Valve assembly

  • EGR cooler assembly

  • ECM

INSPECTION PROCEDURE

Note


  • When replacing the ECM, the ECM needs Registration and Initialization Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing the new ECM, perform all of the initialization/registrations for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK VACUUM SUPPLY


    1. Check that vacuum is supplied to the EGR cooler bypass switching valve assembly.


    NG

    REPAIR OR REPLACE VACUUM SUPPLY Click here

    OK

  2. INSPECT EGR COOLER BYPASS SWITCHING VALVE ASSEMBLY


    1. Inspect the EGR cooler bypass switching valve assembly Click here.


    NG

    REPLACE EGR COOLER BYPASS SWITCHING VALVE ASSEMBLY Click here

    OK

  3. REPLACE EGR COOLER ASSEMBLY


    1. Replace the EGR cooler assembly Click here.


    NEXT

    CHECK WHETHER DTC OUTPUT RECURS (DTC P1401) Click here

  4. REPAIR OR REPLACE VACUUM SUPPLY


    1. Repair or replace the source of the vacuum supply failure.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  5. REPLACE EGR COOLER BYPASS SWITCHING VALVE ASSEMBLY


    1. Replace the EGR cooler bypass switching valve assembly Click here.


    NEXT

  6. CHECK WHETHER DTC OUTPUT RECURS (DTC P1401)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs Click here.

    4. Turn the ignition switch off and wait for 60 seconds or more [A].

    5. Perform road test [B].

    6. Repeat [A] and [B] for the number of trips detected.

    7. Enter the following menus: Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output again.


    NG

    REPLACE ECM Click here

    OK

    END

  7. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs Click here.

    4. Turn the ignition switch off and wait for 60 seconds or more [A].

    5. Perform road test [B].

    6. Repeat [A] and [B] for the number of trips detected.

    7. Enter the following menus: Engine and ECT / Trouble Codes.

    8. Confirm that the DTC is not output again.


    NEXT

    END