DTC Troubleshooting

DTC Troubleshooting: U0155

DTC U0155:

F-CAN Malfunction (ECM-Gauge Control Module)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS.

3. Check for Pending or Confirmed DTCs with the HDS.

Is DTC U0155 indicated?

YES -

Go to step 4.

NO -

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the gauge control module (tach) and the ECM.�

4. Check for body electrical DTCs in the DTCs MENU with the HDS.

Is DTC B1168, B1169, and/or B1178 indicated?

YES -

Go to step 5.

NO -

Do the gauge control module (tach) input test Gauge Control Module (Tach) Input Test.�

5. Turn the ignition switch to LOCK (0).

6. Jump the SCS line with the HDS.

7. Remove the gauge control module (tach) Gauge Control Module Replacement.

8. Disconnect the gauge control module (tach) 36P connector.

9. Disconnect ECM connector A (44P).

10. Check for continuity between ECM connector terminal A36 and gauge control module (tach) 36P connector terminal No. 1.





Is there continuity?

YES -

Go to step 11.

NO -

Repair open in the wire between the ECM (A36) and the gauge control module (tach), then go to step 12.

11. Check for continuity between ECM connector terminal A37 and gauge control module (tach) 36P connector terminal No. 19.





Is there continuity?

YES -

Substitute a known-good gauge control module (tach) Gauge Control Module Replacement, then go to step 12 and recheck. If DTC U0155 is not indicated after substitution, replace the original gauge control module (tach) Gauge Control Module Replacement, then go to step 12.

NO -

Repair open in the wire between the ECM (A37) and the gauge control module (tach), then go to step 12.

12. Reconnect all connectors.

13. Turn the ignition switch to ON (II).

14. Reset the ECM with the HDS.

15. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

16. Check for Pending or Confirmed DTCs with the HDS.

Is DTC U0155 indicated?

YES -

Check for poor connections or loose terminals at the gauge control module (tach) and the ECM, then go to step 1.

NO -

Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�