Automatic Transmission

DTC U0122: Lost Communication with VSA Modulator-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 ON (II).
3. Check whether DTC U0122 is indicated in the DTCs/Freeze Data in PGM-FI Mode Menu with the HDS.

Is DTC U0122 indicated in the PGM-FI system?

YES - Troubleshoot for DTC U0122 in the PGM-FI System.

NO - Go to step 4.

4. Check whether DTC U0122 is indicated in the DTCs/Freeze Data in A/T Mode Menu with the HDS.

Is DTC U0122 indicated?

YES - Go to step 5.

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

5. Update the A/T software in the PCM if it does not have the latest software or substitute a known-good PCM.
6. Turn the ignition switch ON (II).
7. 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 8.

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

Does the result 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 7, go to the indicated DTC's troubleshooting.

NO - If the HDS indicates FAILED, check for poor connections and loose terminals at the VSA modulator-control unit 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, return to step 6 and recheck.

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

Is there malfunction in the F-CAN line between the VSA modulator-control unit and 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.