P1078
DTC P1078: IMT Valve Stuck in Low RPM PositionNOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Do the IMT TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the IMT actuator and the ECM/PCM.
NO - Go to step 4.
4. Turn the ignition switch OFF.
5. Disconnect the IMT actuator 5P connector.
6. Turn the ignition switch ON (II).
7. Check the IMT VALVE SW in the DATA LIST with the HDS.
Is CLOSE indicated?
YES - Go to step 12.
NO - Go to step 8.
8. Turn the ignition switch OFF.
9. Jump the SCS line with the HDS.
10. Disconnect ECM/PCM connector B (44P).
11. Check for continuity between ECM/PCM connector terminal B39 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B39) and the IMT actuator, then go to step 21.
NO - Go to step 28.
12. Check for continuity between ECM/PCM connector terminal B37 and body ground.
Is there continuity ?
YES - Repair short in the wire between the ECM/PCM (B37) and the IMT actuator, then go to step 21.
NO - Go to step 13.
13. Check for continuity between ECM/PCM connector terminal B38 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM/PCM (B38) and the IMT actuator, then go to step 21.
NO - Go to step 14.
14. Check for continuity between IMT actuator 5P connector terminal No. 4 and ECM/PCM connector terminal B37.
Is there continuity?
YES - Go to step 15.
NO - Repair open in the wire between the ECM/PCM (B37) and the IMT actuator, then go to step 21.
15. Check for continuity between IMT actuator 5P connector terminal No. 5 and ECM/PCM connector terminal B38.
Is there continuity?
YES - Go to step 16.
NO - Repair open in the wire between the ECM/PCM (B38) and the IMT actuator, then go to step 21.
16. Remove the IMT actuator.
17. Move the IMT valve by hand.
Does it move smoothly?
YES - Go to step 18.
NO - Replace the IMT valve, then go to step 21.
18. Substitute a known-good IMT actuator.
19. Turn the ignition switch ON (II).
20. Do the IMT TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES - Replace the original IMT actuator, then go to step 21.
NO - Go to step 29.
21. Reconnect all connectors.
22. Turn the ignition switch ON (II).
23. Reset the ECM/PCM with the HDS.
24. Do the ECM/PCM idle learn procedure.
25. Do the IMT TEST in the INSPECTION MENU with the HDS.
26. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1078 indicated?
YES - Check for poor connections or loose terminals at the IMT actuator and the ECM/PCM, then go to step 1.
NO - Go to step 27.
27. Monitor the OBD STATUS for DTC P1078 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 26, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the IMT actuator and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 25.
28. Reconnect all connectors.
29. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
30. Do the IMT TEST in the INSPECTION MENU with the HDS.
31. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1078 indicated?
YES - Check for poor connections or loose terminals at the IMT actuator and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 30. If the ECM/PCM was substituted, go to step 1.
NO - Go to step 32.
32. Monitor the OBD STATUS for DTC P0128 in the DTCs MENU with the HDS.
Does the screen Indicate PASSED?
YES - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCsor DTCs were indicated in step 31, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the IMT actuator and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 30. If the ECM/PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 30.