DTC Troubleshooting

DTC Troubleshooting: P0400, 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 Initial Inspection and Diagnostic Overview.

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 (A/T in P or N, M/T in neutral) 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)
- A/T in D, or M/T in 4th
- Vehicle speed at 25 mph (40 km/h) for 5 minutes or more
- Maintain the vehicle speed at 32 mph (50 km/h) and engine speed between 1,450-3,000 rpm for 1 minute or more with cruise control set

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), or press the engine start/stop button to select the OFF mode.

6. Replace the EGR valve Service and Repair.

7. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

8. Reset the ECM/PCM with the HDS.

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

10. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- A/T in D, or M/T in 4th
- Vehicle speed at 25 mph (40 km/h) for 5 minutes or more
- Maintain the vehicle speed at 32 mph (50 km/h) and engine speed between 1,450-3,000 rpm for 1 minute or more with cruise control set

11. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0400 indicated?

YES -

Check for 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 Pending or Confirmed DTCs were indicated in step 11, go to the indicated DTC's troubleshooting.

NO -

If the screen indicates FAILED, check for leakage between the EGR pipe and the EGR valve, then go to step 1. If the screen indicates NOT COMPLETED, go to step 10.