P1078
DTC P1078: IMRC Valve Stuck Long1. Turn the ignition switch ON (II).
NOTE: Do not start the engine.
2. Make sure the IMRC SOL is ON in the DATA LIST with the HDS.
3. Check the IMRC VLV 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 IMRC actuator and the ECM.
4. Turn the ignition switch OFF.
5. Disconnect the IMRC actuator 5P connector.
6. Turn the ignition switch ON (II).
7. Measure voltage between IMRC actuator 5P connector terminal No.1 and body ground.
Is there about 5 V?
YES - Go to step 8.
NO - Repair open in the wire between the ECM (D12) and the IMRC actuator, then go to step 25.
8. Measure voltage between IMRC actuator 5P connector terminal No.3 and body ground.
Is there about 5 V?
YES - Go to step 9.
NO - Go to step 14.
9. Turn the ignition switch OFF.
10. Jump the SCS line with the HDS.
11. Disconnect ECM connector D (17P).
12. Connect IMRC actuator 5P connector terminal No.2 to body ground with a jumper wire.
13. Check for continuity between ECM connector terminal D10 and body ground.
Is there continuity?
YES - Go to step 17.
NO - Repair open in the wire between the ECM (D10) and the IMRC actuator, then go to step 25.
14. Disconnect ECM connector B (24P).
15. Connect IMRC actuator 5P connector terminal No.3 to body ground with a jumper wire.
16. Check for continuity between ECM connector terminal B11 and body ground.
Is there continuity?
YES - Go to step 31.
NO - Repair open in the wire between the ECM (B11) and the IMRC actuator, then go to step 25.
17. 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 IMRC actuator, then go to step 25.
NO - Go to step 18.
18. Connect IMRC actuator 5P connector terminal No.5 to body ground with a jumper wire.
19. Check for continuity between ECM connector terminal B4 and body ground.
Is there continuity?
YES - Go to step 20.
NO - Repair open in the wire between the ECM (B4) and the IMRC actuator, then go to step 25.
20. 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 IMRC actuator, then go to step 25.
NO - Go to step 21.
21. Connect IMRC actuator 5P connector terminal No.4 to body ground with a jumper wire.
22. Check for continuity between ECM connector terminal 83 and body ground.
Is there continuity?
YES - Go to step 23.
NO - Repair open in the wire between the ECM (B3) and the IMRC actuator, go to step 25.
23. Remove the IMRC actuator.
24. Move the IMRC valve by hand.
Does it move smoothly?
YES - Substitute a known-good IMRC actuator, then go to step 25 and recheck. If DTC P1078 is not indicated, replace the IMRC actuator, then go to step 25. If DTC P1078 is indicated, then 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 ECM with the HDS.
28. Do the ECM idle learn procedure.
29. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1078 is indicated, check for poor connections or loose terminals at the 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 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 IMRC actuator and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 28 and recheck.
31. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
32. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
YES - If DTC P1078 is indicated, check for poor connections or loose terminals at the 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 troubles hooting.
NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM.