DTC Troubleshooting: U0122
DTC U0122: F-CAN Malfunction (PCM-VSA Modulator-Control Unit)
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0122 F-CAN Malfunction (PCM-VSA Modulator-Control Unit)
      

1.
DTC check:

DTC check
?1.
Press the engine start/stop button to select the ON mode.

?2.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0029 F-CAN Malfunction (BUS-OFF (PCM))
     
U0122 F-CAN Malfunction (PCM-VSA Modulator-Control Unit)
      

Are DTC U0029 and U0122 indicated at the same time?

     
YES
     
     
     
     
NO
     
     
     
Go to step 2.
2.
Problem verification:

Problem verification
?1.
Clear the DTC with the HDS.


?2.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0122 F-CAN Malfunction (PCM-VSA Modulator-Control Unit)
      

Is DTC U0122 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 3.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the VSA modulator-control unit and the PCM.?
3.
VSA system check:

VSA system check
?1.
Check for communication to the VSA system with the HDS.

Does the HDS communicate with the VSA modulator-control unit?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
4.
Open wire check (F CAN-H line):

Open wire check (F CAN-H line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS.


?3.
Disconnect the following connectors.

?4.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
PCM connector A (51P): disconnected
 
VSA modulator-control unit 21P connector: disconnected
Test circuit
F CAN-H
Test point 1
VSA modulator-control unit 21P connector No. 8 (WHT)
Test point 2
PCM connector A (51P) No. 9 (WHT)


Is there continuity?

     
YES
     
     
     
The F CAN-H wire is OK. Go to step 5.
     
NO
     
     
     
Repair an open in the F CAN-H wire between the PCM (A9) and the VSA modulator-control unit, then do the repair verification.
5.
Open wire check (F CAN-L line):

Open wire check (F CAN-L line)
?1.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
PCM connector A (51P): disconnected
 
VSA modulator-control unit 21P connector: disconnected
Test circuit
F CAN-L
Test point 1
VSA modulator-control unit 21P connector No. 15 (RED)
Test point 2
PCM connector A (51P) No. 10 (RED)


Is there continuity?

     
YES
     
     
     
The F CAN-L wire is OK. Update the VSA modulator-control unit if it does not have the latest software, then do the repair verification. If DTC U0122 is indicated after updated, replace the original VSA modulator-control unit, then do the repair verification.
     
NO
     
     
     
Repair an open in the F CAN-L wire between the PCM (A10) and the VSA modulator-control unit, then do the repair verification.
Repair verification:

?1.
Reconnect all connectors.

?2.
Exit the SCS mode with the HDS.


?3.
Press the engine start/stop button to select the ON mode.

?4.
Reset the PCM with the HDS.


?5.
Do the PCM idle learn procedure.

?6.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0122 F-CAN Malfunction (PCM-VSA Modulator-Control Unit)
      


Is DTC U0122 indicated?

     
YES
     
     
     
Check for poor connections or loose terminals at the VSA modulator-control unit and the PCM, then go to step 1.
     
NO
     
     
     
Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC’s troubleshooting.?