## DTC Troubleshooting: P0404 (12-4)

DTC P0404 (12-4): | EGR Valve Insufficient Lift

1. | Reset the ECM/PCM.

2. | Start the engine. Hold the engine at 3,000 rpm (min-1) without load (in Park or neutral) until the radiator fan comes on.

3. | Drive the vehicle under load for about 10 minutes. Try to keep the engine speed in the 1,700- 2,500 rpm (min-1) range.

4. | Check the Temporary DTC with the HDS or the scan tool. Is Temporary DTC P0404 indicated? YES - Go to 5. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the EGR valve and at the ECM/PCM.n

5. | Turn the ignition switch OFF.

6. | Disconnect the EGR valve 6P connector.

7. | Start the engine and let it idle.

8. | Measure voltage between the EGR valve 6P connector terminals No. 4 and No. 6. Is there battery voltage? YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/ PCM.n NO - Go to 9.

9. | Turn the ignition switch OFF.

10. | Turn the ignition switch ON (II).

11. | Measure voltage between the EGR valve 6P connector terminals No. 2 and No. 3. Is there about 5 V? YES - Go to 13. NO - Go to 12.

12. | Measure voltage between ECM/PCM connector terminals A10 and A20. Is there about 5 V? YES - Repair open in the wire between the EGR valve and the ECM/PCM (A10, A20).n NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/ PCM.n

13. | Turn the ignition switch OFF.

14. | At the sensor side, measure resistance between the EGR valve 6P connector terminals No. 1 and No. 2. Is there continuity or resistance of 100 kW or higher? YES - Replace the EGR valve.n NO - Go to 15.

15. | Measure resistance between the EGR valve 6P connector terminals No. 1 and No. 3. Is there 100 kW or higher? YES - Replace the EGR valve.n NO - Go to 16.

16. | Reconnect the EGR valve connector.

17. | Turn the ignition switch ON (II).

18. | Measure voltage between ECM/PCM connector terminals A10 and A13. Is there about 1.2 V? YES - Go to 22. NO - Go to 19.

19. | Turn the ignition switch OFF.

20. | Disconnect ECM/PCM connector A (31P).

21. | Check for continuity between ECM/PCM connector terminal A13 and body ground. Is there continuity? YES - Repair short in the wire between the EGR valve and the ECM/PCM (A13).n NO - Repair open in the wire between the EGR valve and the ECM/PCM (A13).n

22. | Turn the ignition switch OFF.

23. | Disconnect the EGR valve 6P connector.

24. | Connect the battery positive terminal to the EGR valve 6P connector terminal No. 4.

25. | Start the engine and let it idle, then connect the battery negative terminal to the EGR valve 6P connector terminal No. 6. Does the engine stall or run rough? YES - Go to 26. NO - Replace the EGR valve.n

26. | Turn the ignition switch OFF.

27. | Disconnect ECM/PCM connector B (24P).

28. | Check for continuity between ECM/PCM connector terminal B14 and body ground. Is there continuity? YES - Repair short in the wire between the EGR valve and the ECM/PCM (B14).n NO - Go to 29.

29. | Connect the EGR valve 6P connector terminal No. 4 and body ground with a jumper wire.

30. | Check for continuity between ECM/PCM connector terminal B14 and the body ground. Is there continuity? YES - Go to 31. NO - Repair open in the wire between the EGR valve and the ECM/PCM (B14).n

31. | Disconnect the jumper wire from the EGR valve 6P connector.

32. | Connect the EGR valve 6P connector terminal No. 6 to body ground with a jumper wire. Is there continuity? YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/ PCM.n NO - Repair open in the wire between the EGR valve and G101.n