DTC Troubleshooting

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.

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
- Drive the vehicle at 25 mph (40 km/h) or less for 5 minutes
- Drive at a steady speed of 25 mph (41 km/h) or more (engine speed between 1,500-3,000 rpm) for 9 seconds or more.

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

Does the HDS indicate FAILED?

YES -

Go to step 5.

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 3 and recheck.

5. Turn the ignition switch to LOCK (0).

6. Replace the EGR valve.

7. Turn the ignition switch to ON (II).

8. Reset the PCM with the HDS.

9. Do the PCM idle learn procedure.

10. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- Transmission in D
- Drive the vehicle at 25 mph (40 km/h) or less for 5 minutes
- Drive at a steady speed of 25 mph (41 km/h) or more (engine speed between 1,500-3,000 rpm) for 9 seconds or more.

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

Is DTC P0400 indicated?

YES -

Check for a leak 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 HDS 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 HDS indicates FAILED, check for a leak between the EGR pipe and the EGR valve, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 10.