DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0400

DTC P0400 : EGR System Leak Detected

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. EGR pipe visual check:

EGR pipe visual check
-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 Service and Repair, then do the repair verification.

2. Problem verification:

Problem verification
-1. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

-2. Test-drive under these conditions:
* Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
* A/T in D, M/T in 4th
* Drive the vehicle at 25 mph (40 km/h) or less for 5 minutes
* Drive at a steady speed of 26 mph (41 km/h) or more (engine speed between 1,600-4,000 rpm) for 11 seconds or more.

-3. Monitor the OBD STATUS for DTC P0400 in the DTCs MENU with the HDS.

Does the HDS indicate FAILED?
-YES- The failure is duplicated. Replace the EGR valve Service and Repair, then do the repair verification.
-NO- If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for an exhaust gas leak between the EGR pipe and the EGR valve. If the HDS indicates NOT COMPLETED, go to step 2-3 and recheck.

Repair verification (OBD STATUS check):

-1. Turn the ignition switch to ON (II).

-2. Reset the ECM/PCM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-3. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.

-4. Test-drive under these conditions:
* Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
* A/T in D, M/T in 4th
* Drive the vehicle at 25 mph (40 km/h) or less for 5 minutes
* Drive at a steady speed of 26 mph (41 km/h) or more (engine speed between 1,600-4,000 rpm) for 11 seconds or more.

-5. Monitor the OBD STATUS for DTC P0400 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
-PASSED- Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck.
-NOT COMPLETED- Meet the test condition, and check the OBD STATUS again.