DTC Troubleshooting
DTC Troubleshooting: P1077
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. 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, and let it idle.
4. Make sure the IMT VALVE CMD is CLOSED in the DATA LIST with the HDS.
Is CLOSED 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 to LOCK (0).
7. Disconnect the IMT actuator 5P connector.
8. Turn the ignition switch to ON (II).
9. Check the IMT VALVE SW in the DATA LIST with the HDS.
Is CLOSED indicated?
YES - Go to step 14.
NO - Go to step 10.
10. Turn the ignition switch to LOCK (0).
11. Jump the SCS line with the HDS.
12. Disconnect PCM connector B (24P).
13. Check for continuity between PCM connector terminal B11 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (B11) and the IMT actuator, then go to step 25.
NO - Go to step 31.
14. Turn the ignition switch to LOCK (0).
15. Jump the SCS line with the HDS.
16. Disconnect PCM connector B (24P).
17. Check for continuity between PCM connector terminal B4 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (B4) and the IMT actuator, then go to step 25.
NO - Go to step 18.
18. Connect IMT actuator 5P connector terminal No. 5 to body ground with a jumper wire.
19. Check for continuity between PCM connector terminal B4 and body ground.
Is there continuity?
YES - Go to step 20.
NO - Repair open in the wire between the PCM (B4) and the IMT actuator, then go to step 25.
20. Check for continuity between PCM connector terminal B3 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (B3) and the IMT actuator, then go to step 25.
NO - Go to step 21.
21. Connect IMT actuator 5P connector terminal No. 4 to body ground with a jumper wire.
22. Check for continuity between PCM connector terminal B3 and body ground.
Is there continuity?
YES - Go to step 23.
NO - Repair open in the wire between the PCM (B3) and the IMT actuator, then go to step 25.
23. Remove the IMT actuator. Service and Repair
24. Move the IMT valve by hand.
Does it move smoothly?
YES - Substitute a known-good IMT actuator, Service and Repair then go to step 25 and recheck. If DTC P1077 is not indicated, replace the IMT actuator, Service and Repair then go to step 25. If DTC P1077 is indicated, go to step 33.
NO - Remove the engine cover, Intake Manifold Removal/Installation and repair the stuck valve. If needed, replace the intake manifold, Intake Manifold Removal/Installation then go to step 25.
25. Reconnect all connectors.
26. Turn the ignition switch to ON (II).
27. Reset the PCM with the HDS.
28. Do the PCM idle learn procedure. PCM Idle Learn Procedure
29. Check for Pending or Confirmed 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, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.
NO - Go to step 30.
30. 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. Service and Repair If any other Pending or Confirmed DTCs were indicated in step 29, go to the indicated DTC's 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, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.
31. Turn the ignition switch to LOCK (0).
32. Reconnect all connectors.
33. 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
34. Check for Pending or Confirmed 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, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.
NO - Go to step 35.
35. 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. Service and Repair If any other Pending or Confirmed DTCs were indicated in step 34, go to the indicated DTC's 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, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.