DTC Troubleshooting: U0122 (126)

DTC U0122:  F-CAN Malfunction (VSA- 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 U0122 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), the VSA modulator-control unit, and the ECM/PCM.n


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

Is VSA DTC 86 indicated?


YES - Go to 5.


NO - Go to 8.


5.Turn the ignition switch OFF.

6.Disconnect the VSA modulator-control unit 37P connector.

7.Check for continuity between VSA modulator-control unit 37P connector terminals No. 1 and No. 15.

 

Is there continuity?


YES - Substitute a known-good VSA modulator-control unit, then go to 15 and recheck. If no DTCs are indicated, replace the original VSA modulator-control unit, then go to 15.


NO - Repair open in the wire between the VSA modulator-control unit (No. 15 (No. 1)*) and the ECM/PCM ( A36 (A37)*), then go to 15.

*: CANL line


8.Check for poor connection at the VSA modulator-control unit 37P connector.

Are the connections OK?


YES - Go to 9.


NO - Repair the poor connection(s), then go to 15.

9.Turn the ignition switch OFF.

10.Disconnect the VSA modulator-control unit 37P connector.

11.Turn the ignition switch ON (II).

12.Measure voltage between VSA modulator-control unit 37P connector terminal No. 28 and body ground.

 

Is there battery voltage?


YES - Go to 13.


NO - Check the No. 4 (7.5 A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the No. 4 (7.5 A) fuse and the VSA modulator-control unit, then go to 15.

13.Turn the ignition switch OFF.

14.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 15 and recheck. If no DTCs are indicated, replace the original VSA modulator-control unit, then go to 15.


NO - Repair open in the wire between the VSA modulator-control unit and body ground (G202), then go to 15.


15.Reconnect the VSA modulator-control unit 37P connector.

16.Turn the ignition switch ON (II).

17.Reset the ECM/PCM with the HDS.

18.Do the ECM/PCM idle learn procedure.

19.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 or loose terminals at the gauge control module (tachometer), the VSA modulator-control unit, 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