DTC Troubleshooting

DTC Troubleshooting: U0131

DTC U0131: F-CAN Malfunction (ECM/PCM-EPS Control Unit)

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. Check for Pending or Confirmed DTCs with the HDS.

Are DTC U0029 and U0131 indicated at the same time?
YES - Go to the troubleshooting for DTC U0029. U0029

NO - Go to step 3.


3. Clear the DTC with the HDS.

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

Is DTC U0131 indicated?
YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EPS control unit and the ECM/PCM.


5. Start the engine, and watch the EPS indicator.

Does the indicator come on and go off?
YES - Go to step 6.

NO - Turn the ignition switch to LOCK (0), and go to symptom troubleshooting for EPS indicator does not go off, and no DTC stored. Symptom Troubleshooting


6. Check for communication to the EPS system with the HDS.

Does the HDS communicate with the EPS control unit?
YES - Go to step 7.

NO - Go to the DLC circuit troubleshooting. Testing and Inspection


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

8. Jump the SCS line with the HDS.

9. Disconnect EPS control unit connector A (11P).

10. Disconnect ECM/PCM connector A (49P).

11. Connect EPS control unit connector terminal A5 to body ground with a jumper wire.






12. Check for continuity between ECM/PCM connector terminal A3 and body ground.

Is there continuity?
YES - Go to step 13.

NO - Repair open in the wire between the ECM/PCM (A3) and the EPS control unit, then go to step 15.






13. Connect EPS control unit connector terminal A3 to body ground with a jumper wire.






14. Check for continuity between ECM/PCM connector terminal A4 and body ground.

Is there continuity?
YES - Substitute a known-good EPS control unit, then go to step 15 and recheck. If DTC U0131 is not indicated after substitution, replace the original EPS control unit, then go to step 15.

NO - Repair open in the wire between the ECM/PCM (A4) and the EPS control unit, then go to step 15.






15. Reconnect all connectors.

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

17. Reset the ECM/PCM with the HDS.

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

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

Is DTC U0131 indicated?
YES - Check for poor connections or loose terminals at the EPS control unit and the ECM/PCM, 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.