DTC Troubleshooting: U0038
DTC U0038: PT-CAN Malfunction (TCM ECU BUS-OFF)
NOTE:
Before you troubleshoot, review the general troubleshooting information.
According to the detected DTC(s), check for the power circuit and the ground circuit of the control unit which cannot communicate with the PCM.

DTC Description
Confirmed DTC
Pending DTC
U0038 PT-CAN Malfunction (TCM ECU BUS-OFF)
    

1.
Problem verification:

Problem verification
?1.
Turn the vehicle to 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
U0038 PT-CAN Malfunction (TCM ECU BUS-OFF)
    

Is DTC U0038 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 TCM 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.?
2.
A/T system check:

A/T system check
?1.
Check for communication to the A/T system with the HDS.

Does the HDS communicate with the A/T system?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
3.
Open wire check (TM-CAN_H line):

Open wire check (TM-CAN_H line)
?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.
PCM connector A (50P)
TCM 50P connector

?4.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
PCM connector A (50P): disconnected
TCM 50P connector: disconnected
Test point 1
TCM 50P connector No. 4
Test point 2
PCM connector A (50P) No. 21

Is there continuity?

     
YES
     
     
     
The TM-CAN_H wire is OK. Go to step 4.
     
NO
     
     
     
Repair an open in the TM-CAN_H wire between the PCM (A21) and the TCM.?
4.
Open wire check (TM-CAN_L line):

Open wire check (TM-CAN_L line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
PCM connector A (50P): disconnected
TCM 50P connector: disconnected
Test point 1
TCM 50P connector No. 12
Test point 2
PCM connector A (50P) No. 20

Is there continuity?

     
YES
     
     
     
The TM-CAN_L wire is OK. 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 U0038 goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Repair an open in the TM-CAN_L wire between the PCM (A20) and the TCM.?