DTC U0401-68; DTC U0402-68: ECM, & TCM Failure

NOTE: 

• Before you troubleshoot, review the general troubleshooting information .
• VSA will set this DTC if any PGM-FI DTC's exist.

• 1. Problem verification:

  1. Turn the vehicle to the ON mode.

  2. Clear the DTC with the HDS.

  3. Turn the vehicle to the OFF (LOCK) mode, then start the engine.

  4. Check for DTCs with the HDS.

  DTC Description	DTC	Freeze Frame
  U0401-68 ECM Failure
  U0402-68 TCM Failure

  Is DTC U0401-68 or U0402-68 indicated?

  YES 

  The failure is duplicated. Go to step 2.

  NO 

  Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting . If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the Freeze data/on-board snapshot.

• 2. PGM-FI DTCs check:

  1. Check for PGM-FI DTCs with the HDS.

  Are any DTCs indicated?

  YES 

  Go to indicated DTCs troubleshooting. After all PGM-FI DTC's have been repaired, return to VSA and clear this code.

  NO 

  Go to step 3.

• 3. PCM check (update or substitution):

  1. Update the PCM if it does not have the latest software , or substitute a known-good PCM .

  2. Clear the DTC with the HDS.

  3. Turn the vehicle to the OFF (LOCK) mode, then start the engine.

  4. Check for DTCs with the HDS.

  DTC Description	DTC	Freeze Frame
  U0401-68 ECM Failure
  U0402-68 TCM Failure

  Is DTC U0401-68 or U0402-68 indicated?

  YES 

  Go to step 4.

  NO 

  If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM .

• 4. VSA modulator-control unit check (update):

  1. Update the VSA modulator-control unit if it does not have the latest software .

  2. Turn the vehicle to the OFF (LOCK) mode, then start the engine.

  3. Check for DTCs with the HDS.

  Is DTC U0401-68 or U0402-68 indicated?

  YES 

  Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit .

  NO 

  Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.