DTC Troubleshooting

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 (in P or N) 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 Acura genuine throttle plate cleaner.

NO - Go to step 5.


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

6. Disconnect the EGR valve 5P connector.

7. At the EGR valve side, measure the resistance between EGR valve 5P connector terminals No. 2 and No. 3.

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 5P connector terminals No. 2 and No. 4.

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

NO - Go to step 9.






9. Check for continuity between EGR valve 5P connector terminal No. 5 and body ground.

Is there continuity?
YES - Go to step 10.

NO - Repair open in the wire between the EGR valve and G101, then go to step 26.






10. Jump the SCS line with the HDS.

11. Disconnect PCM connector B (24P).

12. Check for continuity between PCM connector terminal B5 and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (B5) and the EGR valve, then go to step 27.

NO - Go to step 13.






13. Connect EGR valve 5P connector terminal No. 1 to body ground with a jumper wire.






14. Check for continuity between PCM connector terminal B5 and body ground.

Is there continuity?
YES - Go to step 15.

NO - Repair open in the wire between the PCM (B5) and the EGR valve, then go to step 27.






15. Remove the EGR valve. Service and Repair

16. Clean any carbon build-up on the EGR valve with Acura genuine throttle plate cleaner.

17. Install the EGR valve. Service and Repair

18. Reconnect the EGR valve 5P connector.

19. Reconnect PCM connector B (24P).

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

21. Reset the PCM with the HDS.

22. Do the PCM idle learn procedure. PCM Idle Learn Procedure

23. 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.

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

Is the result OK?
YES - Go to step 33.

NO - Go to step 25.


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

26. Replace the EGR valve. Service and Repair

27. Reconnect all connectors.

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

29. Reset the PCM with the HDS.

30. Do the PCM idle learn procedure. PCM Idle Learn Procedure

31. 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.

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

33. 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 PCM, then go to step 1. If the connections and terminals are OK, go to step 34.

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


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

35. 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.

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

37. 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 PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then go to step 35. If the PCM was substituted, go to step 1.

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