DTC Troubleshooting: U0038
DTC U0038: TM-CAN Malfunction (TCM-PCM)
NOTE:
Before you troubleshoot, review the General Troubleshooting Information.
This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0038 TM-CAN Malfunction (TCM-PCM)
      

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.

?4.
Turn the vehicle to the ON mode.

?5.
Check for Pending or Confirmed DTCs in the PGM-FI system with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
U0038 TM-CAN Malfunction (TCM-PCM)
      

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 and loose terminals between the PCM and the TCM. 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.
Open wire check (TM-CAN_H line and TM-CAN_L line):

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

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

TM-CAN_L line
Test condition
Vehicle OFF (LOCK) mode
 
TCM 50P connector: disconnected
 
PCM connector A (50P): disconnected
Test point 1
TCM 50P connector No. 12
Test point 2
PCM connector A (50P) No. 20

Are there continuity?

     
YES
     
     
     
The TM-CAN_H wire and/or TM-CAN_L wire are not open. Go to step 3.
     
NO
     
     
     
Repair an open in the TM-CAN_H wire and/or TM-CAN_L wire between the PCM and the TCM.?
3.
Shorted wire check (TM-CAN_H line and TM-CAN_L line):

Shorted wire check (TM-CAN_H line and TM-CAN_L line)
?1.
Check for continuity between test points 1 and 2.
TM-CAN_H line
Test condition
Vehicle OFF (LOCK) mode
 
TCM 50P connector: disconnected
 
PCM connector A (50P): disconnected
Test point 1
TCM 50P connector No. 4
Test point 2
Body ground

TM-CAN_L line
Test condition
Vehicle OFF (LOCK) mode
 
TCM 50P connector: disconnected
 
PCM connector A (50P): disconnected
Test point 1
TCM 50P connector No. 12
Test point 2
Body ground

Are there continuity?

     
YES
     
     
     
Repair a short to ground in the TM-CAN_H wire and/or TM-CAN_L wire between the PCM and the TCM.?
     
NO
     
     
     
The TM-CAN_H wire and/or TM-CAN_L wire are 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 this DTC goes away and the PCM was substituted, replace the original PCM.?