DTC Troubleshooting: U0401-68, U0402-68
DTC U0401-68: ECM Failure
DTC U0402-68: TCM Failure
NOTE:
Before you troubleshoot, review the general troubleshooting information.
VSA will set this DTC if any PGM-FI DTC's exist.

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

1.
Problem verification:

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:

PGM-FI DTCs check
?1.
Check for PGM-FI DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
       

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):

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):

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.
DTC Description
DTC
Freeze Frame
     

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.?