DTC Troubleshooting: P1078 (106)
DTC P1078:
 IMT Valve Stuck in Low 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).
  1. Clear the DTC with the HDS.
  1. Do the IMT TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the IMT actuator and the ECM.■
NO -
Go to Step 4 .
  1. Turn the ignition switch OFF.
  1. Disconnect the IMT actuator 5P connector.
  1. Turn the ignition switch ON (II).
  1. Check the IMT VALVE SW in the DATA LIST with the HDS.
Is CLOSE indicated?
YES -
Go to Step 12 .
NO -
Go to Step 8 .
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector B (44P).
  1. Check for continuity between ECM connector terminal B39 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (B39) and the IMT actuator, then go to Step 22 .
NO -
Go to Step 29 .
  1. Check for continuity between ECM connector terminal B37 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (B37) and the IMT actuator, then go to Step 22 .
NO -
Go to Step 13 .
  1. Check for continuity between ECM connector terminal B38 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (B38) and the IMT actuator, then go to Step 22 .
NO -
Go to Step 14 .
  1. Check for continuity between IMT actuator 5P connector terminal No. 4 and ECM connector terminal B37.
Is there continuity?
YES -
Go to Step 15 .
NO -
Repair open in the wire between the ECM (B37) and the IMT actuator, then go to Step 22 .
  1. Check for continuity between IMT actuator 5P connector terminal No. 5 and ECM connector terminal B38.
Is there continuity?
YES -
Go to Step 16 .
NO -
Repair open in the wire between the ECM (B38) and the IMT actuator, then go to Step 22 .
  1. Move the IMT valve by hand.
Does it move smoothly?
YES -
Go to Step 18 .
NO -
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Do the IMT TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
NO -
Go to Step 30 .
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Do the IMT TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1078 indicated?
YES -
Check for poor connections or loose terminals at the IMT actuator and the ECM, then go to Step 1 .
NO -
Go to Step 28 .
  1. Monitor the OBD STATUS for DTC P1078 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 27 , 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 ECM, then go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 26 .
  1. Reconnect all connectors.
  1. Do the IMT TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1078 indicated?
YES -
Check for poor connections or loose terminals at the IMT actuator and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 31 . If the ECM was substituted, go to Step 1 .
NO -
Go to Step 33 .
  1. Monitor the OBD STATUS for DTC P1078 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in Step 32 , 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 ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 31 . If the ECM was substituted, go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 31 .