DTC Troubleshooting: U0146
DTC U0146: F-CAN Malfunction (PCM-CAN Gateway)
NOTE: Before you troubleshoot, review the general troubleshooting information.

DTC Description
Confirmed DTC
Pending DTC
U0146 F-CAN Malfunction (PCM-CAN Gateway)
    

1.
CAN gateway system DTC check:

CAN gateway system DTC check
?1.
Check for CAN gateway system DTCs with the HDS.
DTC Description
DTC
U0029-00 CAN Gateway F-CAN ch A Bus Off
  
U0047-00 CAN Gateway F-CAN ch B Bus Off
  
U3000-49 CAN Gateway Internal Failure
  


Is DTC U0029-00, U0047-00 and/or U3000-49 indicated?

     
YES
     
     
     
     
NO
     
     
     
Go to step 2.
2.
F-CAN circuit communication check:

F-CAN circuit communication check
?1.
Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.

Which result is indicated?

     
PCM (Bus A) is Not Available
     
     
     
Go to step 3.
     
PCM is Detected
     
     
     
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the CAN gateway and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot.?
3.
Open wire check (F-CAN A_L, F-CAN A_H lines):

Open wire check (F-CAN A_L, F-CAN A_H lines)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Jump the SCS line with the HDS, and wait more than 1 minute.


?3.
Disconnect the following connectors.
CAN gateway 16P connector
PCM connector A (51P)

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
CAN gateway 16P connector: disconnected
 
PCM connector A (51P): disconnected
Test point 1
CAN gateway 16P connector (female terminals) No. 3:
Test point 2
PCM connector A (51P) No. 2

Test point 1
CAN gateway 16P connector (female terminals) No. 11:
Test point 2
PCM connector A (51P) No. 1


Is there continuity?

     
YES
     
     
     
The F-CAN A_L and F-CAN A_H wires are OK. Check for poor connections or loose terminals at the CAN gateway and the PCM. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC U0146 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the F-CAN A_H wire or the F-CAN A_L wire between the PCM (A1, A2) and the CAN gateway.?