Automatic Transmission

DTC U0122: Lost Communication with VSA Control Unit

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information.

1. Clear the DTC with the HDS.
2. Turn the ignition switch to ON (II).
3. Check that DTC U0122 recurs.

Is DTC U0122 indicated?

YES - Go to step 4.

NO - Intermittent failure, the system is OK at this time.

4. Check whether any DTC is indicated in the DTCs/Freeze Data in VSA Mode Menu with the HDS.

Is any DTC indicated in the VSA?

YES - Troubleshoot for the indicated DTC in the VSA system.

NO - Go to step 5.

5. Turn the ignition switch to LOCK (0).
6. Jump the SCS line with the HDS.
7. Disconnect PCM connector A (44P).
8. Disconnect the VSA modulator-control unit connector.
9. Check for continuity between PCM connector terminal A36 and VSA modulator-control unit connector terminal No. 39, and between A37 and terminal No. 38.





Is there continuity?

YES - Go to step 10.

NO - Go to step 14.

10. Update the A/T software in the PCM if it does not have the latest software, or substitute a known-good PCM.
11. Start the engine, and let it idle for 2 minutes.
12. Check for DTC(s) in the DTCs/Freeze Data in A/T Mode Menu with the HDS.

Is DTC U0122 indicated?

YES - If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.

NO - Go to step 13.

13. Monitor the OBD STATUS for U0122 in the DTCs/Freeze Data in A/T Mode Menu for a pass/fail.

Does the HDS indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other DTCs were indicated on step 12, go to the indicated DTC's troubleshooting.

NO - Check for poor connections and loose terminals at the VSA modulator-control unit and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.

14. Check the communication line between the VSA modulator-control unit and the gauge control module with the HDS.

Is there a malfunction in the F-CAN line between the VSA modulator-control unit and the gauge control module?

YES - Repair open in the wires between the VSA modulator-control unit connector and the CAN communication lines.

NO - Substitute a known-good VSA modulator-control unit, then recheck. If the symptom/indication goes away with a known-good VSA modulator-control unit, replace the original VSA modulator-control unit.