DTC Troubleshooting: U0155 (126)

DTC U0155:  F-CAN Malfunction (Gauge Control Module-ECM/PCM)


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).

2.Clear the DTC with the HDS.

3.Check for Temporary DTCs or DTCs with the HDS.

Is DTC U0155 indicated?


YES - Go to 4.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the gauge control module (tachometer) and the ECM/PCM.n


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

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


YES - Go to 5.


NO - Do the gauge control module input test.n


5.Turn the ignition switch OFF.

6.Jump the SCS line with the HDS.

7.Remove the gauge control module (tachometer).

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

9.Disconnect ECM/PCM connector A (44P).

10.Connect gauge control module (tachometer) 36P connector terminal No. 1 to body ground with a jumper wire.

 

11.Check for continuity between ECM/PCM connector terminal A36 and body ground.

 

Is there continuity?


YES - Go to 12.


NO - Repair open in the wire between the ECM/PCM (A36) and the gauge control module (tachometer), then go to 14.

12.Connect gauge control module (tachometer) 36P connector terminal No. 19 to body ground with a jumper wire.

 

13.Check for continuity between ECM/PCM connector terminal A37 and body ground.

 

Is there continuity?


YES - Substitute a known-good gauge control module (tachometer), then go to 14 and recheck. If no DTCs are indicated, replace the original gauge control module (tachometer), then go to 14.


NO - Repair open in the wire between the ECM/PCM (A37) and the gauge control module (tachometer), then go to 14.

14.Reconnect all connectors.

15.Turn the ignition switch ON (II).

16.Reset the ECM/PCM with the HDS.

17.Do the ECM/PCM idle learn procedure.

18.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC U0155 is indicated, check for poor connections or loose terminals at the gauge control module (tachometer) and the ECM/PCM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Troubleshooting is complete.n