DTC Troubleshooting

DTC U0122: F-CAN Malfunction (ECM/PCM-VSA Modulator-Control Unit)

NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
- If DTC U0073 is stored at the same time as DTC U0122, troubleshoot DTC U0073 first, then recheck for DTC U0122.

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 U0122 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, the VSA modulator-control unit, and the ECM/PCM.

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

Is VSA system DTC 86 indicated?

YES - Go to step 5.

NO - Go to step 13.

5. Turn the ignition switch OFF.
6. Jump the SCS line with the HDS.
7. Disconnect the VSA modulator-control unit 37P connector.
8. Disconnect ECM/PCM connector E (31P).
9. Connect VSA modulator-control unit 37P connector terminal No. 15 to body ground with a jumper wire.






10. Check for continuity between ECM/PCM connector terminal E15 and body ground.






Is there continuity?

YES - Go to step 11.

NO - Repair open in the wire between the ECM/PCM (E15) and the VSA modulator-control unit, then go to step 20.

11. Connect VSA modulator-control unit 37P connector terminal No. 1 to body ground with a jumper wire.






12. Check for continuity between ECM/PCM connector terminal E26 and body ground.






Is there continuity?

YES - Substitute a known-good VSA modulator-control unit, then go to step 20 and recheck. If DTC U0122 is not indicated, replace the original VSA modulator-control unit, then go to step 20.

NO - Repair open in the wire between the ECM/PCM (E26) and the VSA modulator-control unit, then go to step 20.

13. Check for poor connections or loose terminals at the VSA modulator-control unit 37P connector.

Are the connections and terminals OK?

YES - Go to step 14.

NO - Repair the connections or terminals, then go to step 21.

14. Turn the ignition switch OFF.
15. If not already done, disconnect the VSA modulator-control unit 37P connector.
16. Turn the ignition switch ON (II).
17. Measure voltage between VSA modulator-control unit 37P connector terminal No. 28 and body ground.






Is there battery voltage?

YES - Go to step 18.

NO - Check the No. 18 (15 A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the No. 18 (15 A) fuse and the VSA modulator-control unit, then go to step 20.

18. Turn the ignition switch OFF.
19. Check for continuity between VSA modulator-control unit 37P connector terminal No. 36 and body ground.






Is there continuity?

YES - Substitute a known-good VSA modulator-control unit, then go to step 15 and recheck. If DTC U0122 is not indicated, replace the original VSA modulator-control unit, then go to step 20.

NO - Repair open in the wire between the VSA modulator-control unit and G203, then go to step 15.

20. Reconnect all connector.
21. Turn the ignition switch ON (II).
22. Reset the ECM/PCM with the HDS.
23. Do the ECM/PCM idle learn procedure.
24. Check for Temporary DTCs or DTCs with the HDS.

Is DTC U0122 indicated?

YES - Check for poor connections or loose terminals at the VSA modulator-control unit, and the ECM/PCM, then go to step 1.

NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.