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 Initial Inspection and Diagnostic Overview.
1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
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 throttle plate cleaner.
NO -
Go to step 5.
5. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
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 an open in the wire between the EGR valve and G101 Engine Wire Harness, then go to step 26.
10. Jump the SCS line with the HDS.
11. Disconnect PCM connector C (49P).
12. Check for continuity between PCM connector terminal C10 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PCM (C10) and the EGR valve, then go to step 26.
NO -
Go to step 13.
13. Check for continuity between PCM connector terminal C10 and EGR valve 5P connector terminal No. 1.
Is there continuity?
YES -
Go to step 14.
NO -
Repair an open in the wire between the PCM (C10) and the EGR valve, then go to step 26.
14. Remove the EGR valve Service and Repair.
15. Clean any carbon build-up on the EGR valve with throttle plate cleaner.
16. Reinstall the EGR valve Service and Repair.
17. Reconnect the EGR valve 5P connector.
18. Reconnect PCM connector C (49P).
19. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
20. Reset the PCM with the HDS.
21. Do the PCM idle learn procedure PCM Idle Learn Procedure.
22. 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.
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), or press the engine start/stop button to select the OFF mode.
25. Replace the EGR valve Service and Repair.
26. Reconnect all connectors.
27. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
28. Reset the PCM with the HDS.
29. Do the PCM idle learn procedure PCM Idle Learn Procedure.
30. 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.
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 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 are indicated, go to the indicated DTC's troubleshooting.
33. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
34. 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.
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 PCM. If the PCM was updated, substitute a known-good PCM, then go to step 34. 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.