P1077
DTC P1077: IMT (IMRC) Valve Stuck ShortNOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
1. Start the engine, and let it idle.
2. Check the IMT (IMRC) VALVE CMD in the DATA LIST with the HDS.
Is CLOSE indicated?
YES - Go to step 3.
NO - Go to step 29.
3. Check the IMT (IMRC) VALVE SW in the DATA LIST with the HDS.
Is OPEN indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the IMT (IMRC) actuator and the ECM.
4. Turn the ignition switch OFF.
5. Disconnect the IMT (IMRC) actuator 5P connector.
6. Turn the ignition switch ON (II).
7. Check the IMT (IMRC) VLV 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 connector B (24P).
11. Check for continuity between ECM connector terminal B11 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (B11) and the IMT (IMRC) actuator, then go to step 23.
NO - Go to step 29.
12. Turn the ignition switch OFF.
13. Jump the SCS line with the HDS.
14. Disconnect ECM connector B (24P).
15. Check for continuity between ECM connector terminal B4 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (B4) and the IMT (IMRC) actuator, then go to step 23.
NO - Go to step 16.
16. Connect IMT (IMRC) actuator 5P connector terminal No. 5 to body ground with a jumper wire.
17. Check for continuity between ECM connector terminal B4 and body ground.
Is there continuity?
YES - Go to step 18.
NO - Repair open in the wire between the ECM (B4) and the IMT (IMRC) actuator, then go to step 23.
18. Check for continuity between ECM connector terminal B3 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (B3) and the IMT (IMRC) actuator, then go to step 23.
NO - Go to step 19.
19. Connect IMT (IMRC) actuator 5P connector terminal No. 4 to body ground with a jumper wire.
20. Check for continuity between ECM connector terminal B3 and body ground.
Is there continuity?
YES - Go to step 21.
NO - Repair open in the wire between the ECM (B3) and the IMT (IMRC) actuator, then go to step 23.
21. Remove the IMT (IMRC) actuator.
22. Move the IMT (IMRC) valve by hand.
Does it move smoothly?
YES - Substitute a known-good IMT (IMRC) actuator, then go to step 23 and recheck. If DTC P1077 is not indicated, replace the IMT (IMRC) actuator, then go to step 23. If DTC P1077 is indicated, go to step 29.
NO - Remove the intake manifold upper 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 ECM with the HDS.
26. Do the ECM idle learn procedure.
27. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1077 is indicated, check for poor connections or loose terminals at the IMT (IMRC) actuator and the ECM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
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 - Troubleshooting is complete.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the IMT (IMRC) actuator and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 26 and recheck.
29. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
30. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1077 is indicated, check for poor connections or loose terminals at the IMT (IMRC) actuator and the ECM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM.