Diesel Data: Automotive Repair

A/T System




DTC Troubleshooting: U0122 (107)

DTC U0122:

F-CAN Malfunction (PCM - VSA Modulator-Control Unit)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot with the HDS, and review General Troubleshooting Information. How To Troubleshoot The A/T System

1. Clear the DTC with the HDS.

2. Check for Pending or Confirmed DTCs in the PGM-FI SYSTEM with the HDS.

Is DTC U0122 indicated in the PGM-FI SYSTEM?

YES -

Troubleshoot for U0122 in the PGM-FI SYSTEM; K24Z1 engine DTC Troubleshooting
NO -

Go to step 3.

3. Check for Pending or Confirmed DTCs in the A/T SYSTEM with the HDS.

Is DTC U0122 indicated in the A/T SYSTEM?

YES -

Go to step 4.

NO -

Intermittent failure, the system is OK at this time. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.�

4. Update the A/T software in the PCM if it does not have the latest software;, or substitute a known-good PCM; Initial Inspection and Diagnostic Overview,.

5. Start the engine in P, and wait for at least 2 minutes.

6. Check for Pending or Confirmed DTCs in the A/T SYSTEM with the HDS.

Is DTC U0122 indicated in the A/T SYSTEM?

YES -

Check for poor connections or loose terminals between the VSA modulator-control unit and the PCM. If the PCM was updated, substitute a known-good PCM; Initial Inspection and Diagnostic Overview, then go to step 5. If the PCM was substituted, reinstall the original PCM, then go to step 1.

NO -

Go to step 7.

7. Monitor the OBD STATUS for U0122 in the DTCs MENU with the HDS.

Does the HDS indicate PASSED?

YES -

If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM; K24Z6 engine Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 6 U0122, go to the indicated DTC's troubleshooting.�

NO -

If the HDS indicates FAILED, check for poor connections or loose terminals between the VSA modulator-control unit and the PCM. If the PCM was updated, substitute a known-good PCM; Initial Inspection and Diagnostic Overview, then go to step 5. If the PCM was substituted, reinstall the original PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 5.