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DTC P0400: EGR System Leak Detected

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review GENERAL TROUBLESHOOTING INFORMATION .
  1. Check for a loose or damaged EGR pipe.

    Is the EGR pipe OK? 

    YES  - Go to step  2.

    NO  - Reconnect or replace the EGR pipe, then go to step  7.

  2. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
  3. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
    • Transmission in D
    • Vehicle speed at 25 mph (40 km/h) for 5 minutes or more, then maintain a vehicle speed of 32 mph (50 km/h) for 5 minutes or more with cruise control set.
    • Maintain the vehicle speed at 32 mph (50 km/h) and engine speed between 1,500-3,000 rpm for 1 minute or more)
  4. Monitor the OBD STATUS for DTC P0400 in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    YES  - Go to step  5.

    NO  - If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for exhaust gas leakage between the EGR pipe and the EGR valve. If the screen indicates NOT COMPLETED, go to step  3 and recheck.

  5. Turn the ignition switch to LOCK (0).
  6. Replace the EGR valve (see EGR VALVE REPLACEMENT  ).
  7. Turn the ignition switch to ON (II).
  8. Reset the PCM with the HDS.
  9. Do PCM IDLE LEARN PROCEDURE ).
  10. Test-drive under these conditions:
    • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
    • Transmission in D
    • Vehicle speed at 25 mph (40 km/h) for 5 minutes or more, then maintain a vehicle speed of 32 mph (50 km/h) for 5 minutes or more with cruise control set
    • Maintain the vehicle speed at 32 mph (50 km/h) and engine speed between 1,500-3,000 rpm for 1 minute or more)
  11. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC P0400 indicated? 

    YES  - Check for exhaust gas leakage between the EGR pipe and the EGR valve, then go to step  1.

    NO  - Go to step  12.

  12. Monitor the OBD STATUS for DTC P0400 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    YES  - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 11, go to the indicated DTCs troubleshooting.

    NO  - If the screen indicates FAILED, check for exhaust gas leakage between the EGR pipe and the EGR valve, then go to step  1. If the screen indicates NOT COMPLETED, go to step  10.

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