P0404

DTC Troubleshooting: P0404

DTC P0404: EGR Valve Circuit Range/Performance Problem

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes

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

2. Clear the DTC with the HDS.

3. 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.

4. Do the EGR TEST in the INSPECTION MENU with the HDS.

Is the result OK?
YES - Intermittent failure, the system is OK at this time. Clean any carbon build-up on the EGR valve with throttle plate cleaner.

NO - Go to step 5.


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

6. Disconnect the EGR valve 6P connector.

7. At the EGR valve side, measure the resistance between EGR valve 6P connector terminals No. 1 and No. 2.

Is there 100 kOhms or more?
YES - Go to step 25.

NO - Go to step 8.






8. At the EGR valve side, measure the resistance between EGR valve 6P connector terminals No. 1 and No. 3.

Is there 100 kOhms or more?
YES - Go to step 25.

NO - Go to step 9.






9. Check for continuity between EGR valve 6P connector terminal No. 6 and body ground.

Is there continuity?
YES - Go to step 10.

NO - Repair open in the wire between the EGR valve and G101; A/T, M/T, then go to step 26.






10. Jump the SCS line with the HDS.

11. Disconnect ECM/PCM connector B (44P).

12. Check for continuity between ECM/PCM connector terminal B2 and body ground.

Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B2) and the EGR valve, then go to step 26.

NO - Go to step 13.






13. Check for continuity between ECM/PCM connector terminal B2 and EGR valve 6P connector terminal No. 4.

Is there continuity?
YES - Go to step 14.

NO - Repair open in the wire between the ECM/PCM (B2) and the EGR valve, then go to step 26.






14. Remove the EGR valve. Service and Repair

15. Clean the intake manifold EGR port and the EGR pipe Service and Repair with throttle plate cleaner. Also, clean the passage inside the EGR valve with throttle plate cleaner.

16. Install the EGR valve. Service and Repair

17. Reconnect the EGR valve 6P connector.

18. Reconnect ECM/PCM connector B (44P).

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

20. Reset the ECM/PCM with the HDS.

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

22. 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.

23. Do the EGR TEST in the INSPECTION MENU with the HDS.

Is the result OK?
YES - Go to step 32.

NO - Go to step 24.


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

25. Replace the EGR valve. Service and Repair

26. Reconnect all connectors.

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

28. Reset the ECM/PCM with the HDS.

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

30. 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.

31. Do the EGR TEST in the INSPECTION MENU with the HDS.

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

Is DTC P0404 indicated?
YES - Check for poor connections or loose terminals at the EGR valve and the ECM/PCM, then go to step 1. If the connections and terminals are OK, go to step 33.

NO - Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.


33. Update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM. Reading and Clearing Diagnostic Trouble Codes

34. 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.

35. Do the EGR TEST in the INSPECTION MENU with the HDS.

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

Is DTC P0404 indicated?
YES - Check for poor connections or loose terminals at the EGR valve and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, Reading and Clearing Diagnostic Trouble Codes then go to step 34. If the ECM/PCM was substituted, go to step 1.

NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. Service and Repair If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.