## DTC Troubleshooting: U0073 (126)

DTC U0073: | F-CAN Malfunction (Bus-Off)

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

2. | Clear the DTC with the HDS.

3. | Start the engine.

4. | Check for Temporary DTCs or DTCs with the HDS. Is DTC U0073 indicated? YES - Go to 5. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VSA modulator-control unit or the ECM.n

5. | Turn the ignition switch OFF, and wait 10 seconds.

6. | Disconnect the VSA modulator-control unit 46P connector and yawrate/lateral acceleration sensor 4P connector.

7. | Turn the ignition switch ON (II).

8. | Measure voltage between VSA modulator-control unit 46P connector terminals No. 38, No. 39 and body ground individually. Is there battery voltage? YES - Go to 9. NO - Go to 12.

9. | Turn the ignition switch OFF, and wait 10 seconds.

10. | Disconnect ECM connector No. 4 (40P).

11. | Measure voltage between VSA modulator-control unit 46P connector terminals No. 38, No. 39 and body ground individually. Is there battery voltage? YES - Repair short to power in the wire between ECM connector No. 4 terminal No. 40 (CANH line), terminal No. 30 (CANL line) and VSA modulator-control unit 46P connector, then go to 19. NO - Substitute a known good ECM, then go to 19.

12. | Turn the ignition switch OFF and wait 10 seconds.

13. | Check for continuity between VSA modulator-control unit 46P connector terminals No. 38, No. 39 and body ground individually. Is there continuity? YES - Go to 14. NO - Go to 16.

14. | Disconnect ECM connector No. 4 (40P).

15. | Check for continuity between VSA modulator-control unit 46P connector terminals No. 38, No. 39 and body ground individually. Is there continuity? YES - Repair short to ground in the wire between ECM connector No. 4 terminal No. 40 (CANH line), terminal No. 30 (CANL line) and VSA modulator-control unit 46P connector, then go to 19. NO - Substitute a known good ECM, then go to 19.

16. | Check for resistance between VSA modulator-control unit 46P connector terminals No. 38 and No. 39. Is there about 120±12 W? YES - Substitute a known good VSA modulator-control unit, and the yawrate/lateral acceleration sensor unit one at a time until the DTCs are no longer present, then replace the control module that made the DTCs go away. If the symptom does not go away, substitute a known good ECM, then go to 19. NO - Go to 17.

17. | Disconnect ECM connector No. 4 (40P).

18. | Check for continuity between VSA modulator-control unit 46P connector terminals No. 38 and No. 39. Is there continuity? YES - Repair short in the wire between ECM connector No. 4 terminal No. 40 (CANH line), terminal No. 30 (CANL line) and VSA modulator-control unit connector, then go to 19. NO - Substitute a known good ECM, then go to 19.

19. | Turn the ignition switch OFF, and wait 10 seconds.

20. | Reconnect all connectors.

21. | Turn the ignition switch ON (II).

22. | Reset the ECM with the HDS.

23. | Do the ETCS learn procedure.

24. | Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC U0073 is indicated, check for poor connections and loose terminals at the VSA modulator-control unit and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Troubleshooting is complete. If the ECM was substituted, replace the original ECM.n