DTC U0146 (A/T)

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 U0146 : F-CAN Malfunction (TCM - CAN Gateway)

NOTE: Before you troubleshoot, review the General Troubleshooting Information .

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
U0146 F-CAN Malfunction (TCM - CAN Gateway)

DTC (A/T)

CAN gateway system DTC check

-1. Check for CAN gateway system DTCs with the HDS.

DTC Description	DTC

Are any DTCs indicated?

YES

Go to the indicated DTC's troubleshooting for CAN gateway system .

Go to step 2.

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.

F-CAN Bus Connected Unit Check

Does the TCM detect the CAN gateway Bus channels A and D?

Bus A is Not Available

Go to step 3.

Bus D is Not Available

Go to step 4.

Bus A and D are Available

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the CAN gateway 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.

Open wire check (F-CAN A_H line, F-CAN A_L line)

-1. Turn the vehicle to the OFF (LOCK) mode.

-2. Disconnect the following connectors.

CAN gateway 16P connector

TCM connector A (23P)

-3. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 16P connector: disconnected
	TCM connector A (23P): disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 3:
Test point 2	TCM connector A (23P) No. 19

Test point 1	CAN gateway 16P connector (female terminals) No. 11:
Test point 2	TCM connector A (23P) No. 18

Courtesy of HONDA, U.S.A., INC.

Is there continuity?

YES

The F-CAN A_H wire and the F-CAN A_L wire are OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good TCM , then recheck. If this DTC goes away and the TCM was substituted, replace the original TCM .

Repair an open in the F-CAN A_H wire and/or the F-CAN A_L wire between the CAN gateway and the TCM.

Open wire check (F-CAN D_H line, F-CAN D_L line)