DTC U0029-00 (VSA Control Unit: With ACC)

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 U0029-00 : CAN Communication Failure (Bus OFF Ch 1)

NOTE:

This DTC is stored by communication failure between the F-CAN line and the VSA modulator-control unit. When DTC U0029-00 is indicated, the F-CAN line has already returned to normal. Check for loose terminals and poor connections at the connectors. If the connectors are OK, clear the DTC and follow this troubleshooting.
Troubleshoot any PGM-FI system DTCs first .
Before you troubleshoot, review the general troubleshooting information .

DTC Description	DTC
U0029-00 CAN Communication Failure (Bus OFF Ch 1)

DTC (VSA)

CAN gateway system DTC check

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

DTC Description	DTC

DTC (CAN gateway)

Are any DTCs indicated?

YES

Go to indicated DTC's troubleshooting .

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 CAN gateway detect the VSA modulator-control unit Bus channels A and B?

Bus A is Not Available

Go to step 3.

Bus B is Not Available

Go to step 4.

Bus A and B are Available

Check for loose terminals and poor connections in the VSA modulator-control unit connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or replace the VSA modulator-control unit .

Open wire check (F-CAN A H, F-CAN A L lines)

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

-2. Disconnect the following connectors.

CAN gateway 16P connector

VSA modulator-control unit 46P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 16P connector: disconnected
	VSA modulator-control unit 46P connector: disconnected
Test point 1	CAN gateway 16P connector (female terminals) No. 3:
Test point 2	VSA modulator-control unit 46P connector No. 20

Test point 1	CAN gateway 16P connector (female terminals) No. 11:
Test point 2	VSA modulator-control unit 46P connector No. 21

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

Is there continuity?

YES

The F-CAN A H and F-CAN A L wires are OK. Check for loose terminals and poor connections in the VSA modulator-control unit connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or replace the VSA modulator-control unit .

Repair an open in the wire between the VSA modulator-control unit and the CAN gateway.

Open wire check (F-CAN B H, F-CAN B L lines)