DTC Troubleshooting: U0122 (126)

DTC U0122:  F-CAN Malfunction (VSA-ECM)

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 U0122 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 ECM connector No. 4 (40P) and VSA modulator-control unit 46P connector.

7.Connect the ECM test harness and the test pin box between the ECM and connector.

8.Connect the VSA modulator-control unit 46P connector terminal No. 39 to body ground with a jumper wire.

 

9.Check for continuity between test pin box terminal No. 121 and body ground.

Is there continuity?


YES - Go to 10.


NO - Repair open in the wire between the ECM connector No. 4 terminal No. 40 (test pin box terminal No. 121), and the VSA modulator-control unit connector, then go to 12.


10.Connect the VSA modulator-control unit 46P connector terminal No. 38 to body ground with a jumper wire.

 

11.Check for continuity between test pin box terminal No. 111 and body ground.

Is there continuity?


YES - Substitute a known good VSA modulator-control unit, and the yawrate/lateral acceleration sensor 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 12.


NO - Repair open in the wire between ECM connector No. 4 terminal No. 30 (test pin box terminal No. 111), and the VSA modulator-control unit connector, then go to 12.


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

13.Reconnect all connectors.

14.Turn the ignition switch ON (II).

15.Reset the ECM with the HDS.

16.Do the ETCS learn procedure.

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

Are any Temporary DTCs or DTCs indicated?


YES - If DTC U0122 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