DTC Troubleshooting

DTC P1077: IMT Valve Stuck in High RPM Position

NOTE: 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. Start the engine, and let it idle.
4. Check the IMT VALVE CMD in the DATA LIST with the HDS.

Is CLOSE indicated?

YES - Go to step 5.

NO - Go to step 29.

5. Check the IMT VALVE SW in the DATA LIST with the HDS.

Is OPEN indicated?

YES - Go to step 6.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the IMT actuator and the PCM.

6. Turn the ignition switch OFF.
7. Disconnect the IMT actuator 5P connector.
8. Turn the ignition switch ON (II).
9. Check the IMT VALVE SW in the DATA LIST with the HDS.

Is CLOSE indicated?

YES - Go to step 14.

NO - Go to step 10.

10. Turn the ignition switch OFF.
11. Jump the SCS line with the HDS.
12. Disconnect PCM connector B (49P).




13. Check for continuity between PCM connector terminal B19 and body ground.

Is there continuity?

YES - Repair short in the wire between the PCM (B19) and the IMT actuator, then go to step 23.

NO - Go to step 30.

14. Turn the ignition switch OFF.
15. Jump the SCS line with the HDS.
16. Disconnect PCM connector C (49P).




17. Check for continuity between PCM connector terminal C48 and body ground.

Is there continuity?

YES - Repair short in the wire between the PCM (C48) and the IMT actuator, then go to step 23.

NO - Go to step 18.




18. Check for continuity between IMT actuator 5P connector terminal No. 5 and PCM connector terminal C48.

Is there continuity?

YES - Go to step 19.

NO - Repair open in the wire between the PCM (C48) and the IMT actuator, then go to step 23.




19. Check for continuity between PCM connector terminal C49 and body ground.

Is there continuity?

YES - Repair short in the wire between the PCM (C49) and the IMT actuator, then go to step 23.

NO - Go to step 20.




20. Check for continuity between IMT actuator 5P connector terminal No. 4 and PCM connector terminal C49.

Is there continuity?

YES - Go to step 21.

NO - Repair open in the wire between the PCM (C49) and the IMT actuator, then go to step 23.

21. Remove the IMT actuator.
22. Move the IMT valve by hand.

Does it move smoothly?

YES - Substitute a known-good IMT actuator, then go to step 23 and recheck. If DTC P1077 is not indicated, replace the IMT actuator, then go to step 23. If DTC PI077 is indicated, go to step 31.

NO - Remove the engine cover, and repair the stuck valve. If necessary, replace the intake manifold, then go to step 23.

23. Reconnect all connectors.
24. Turn the ignition switch ON (II).
25. Reset the PCM with the HDS.
26. Do the PCM idle learn procedure.
27. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1077 indicated?

YES - Check for poor connections or loose terminals at the IMT actuator and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 28.

28. Monitor the OBD STATUS for DTC P1077 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Temporary DTCs or DTCs were indicated in step 27, 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 PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.

29. Turn the ignition switch OFF.
30. Reconnect all connectors.
31. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
32. Start the engine, and let it idle.
33. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1077 indicated?

YES - Check for poor connections or loose terminals at the IMT actuator and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 34.

34. Monitor the OBD STATUS for DTC P1077 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Temporary DTCs or DTCs were indicated in step 33, 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 PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.