DTC Troubleshooting: U1101
DTC U1101: F-CAN Malfunction (PCM-ACM)
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
U1101 F-CAN Malfunction (PCM-ACM)
      

1.
Problem verification:

Problem verification
?1.
Press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U1101 F-CAN Malfunction (PCM-ACM)
      

Is DTC U1101 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the engine mount control unit and the PCM.?
2.
ACM system check:

ACM system check
?1.
Check for ACM system DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P15AB Engine Mount Control Unit Power Source Circuit Low Voltage
      

Is DTC P15AB indicated?

     
YES
     
     
     
     
NO
     
     
     
Go to step 3.
3.
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
 
Engine mount control unit 16P connector: disconnected
Test circuit
F CAN-H
Test point 1
Engine mount control unit 16P connector No. 13 (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 4.
     
NO
     
     
     
Repair an open in the F CAN-H wire between the PCM (A9) and the engine mount control unit, then do the repair verification.
4.
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
 
Engine mount control unit 16P connector: disconnected
Test circuit
F CAN-L
Test point 1
Engine mount control unit 16P 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. Substitute a known-good engine mount control unit, then go to step 1 and recheck. If DTC U1101 is not indicated after substitution, replace the original engine mount control unit, then do the repair verification.
     
NO
     
     
     
Repair an open in the F CAN-L wire between the PCM (A10) and the engine mount 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
U1101 F-CAN Malfunction (PCM-ACM)
      


Is DTC U1101 indicated?

     
YES
     
     
     
Check for poor connections or loose terminals at the engine mount 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.?