DTC U0038

WARNING: This page is about a different car, the 2022 Honda Accord, 2021 Honda Accord, 2020 Honda Accord, 2019 Honda Accord, and 2018 Honda Accord. However, it is still accessible from the selected car via links, so may be relevant.

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)

DTC (PGM-FI)

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

Go to step 2.

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 .

CVT system check
-1. Check for communication to the CVT system with the HDS.

Does the HDS communicate with the CVT system?

YES

Go to step 3.

NO

Go to the symptom troubleshooting for CVT system .

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

Go to step 4.

Repair an open in the TM-CAN_H wire between the PCM (A21) and the TCM.

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 .

Repair an open in the TM-CAN_L wire between the PCM (A20) and the TCM.