P1077
DTC P1077: IMT Valve Stuck in High 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. Start the engine, and let it idle.
4. Make sure the IMT VALVE CMD is CLOSED 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, 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 CLOSED 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 (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 OFF.
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.
24. Move the IMT valve by hand.
Does it move smoothly?
YES - Substitute a known-good IMT actuator, then go to step 25 and recheck. If DTC P1077 is not indicated, replace the IMT actuator, then go to step 25. If DTC P1077 is indicated, go to step 31.
NO - Remove the intake manifold upper cover, and repair the stuck valve. If necessary, replace the intake manifold, then go to step 25.
25. Reconnect all connectors.
26. Turn the ignition switch ON (II).
27. Reset the PCM with the HDS.
28. Do the PCM idle learn procedure.
29. 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 actuator and the PCM, 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 30.
30. 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 actuator and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 28 and recheck.
31. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
32. 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 actuator and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM.