DTC U0029-00 (Electric Brake Booster Control Unit: Without 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 (Ch1 Bus OFF)

NOTE:

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

DTC Description	DTC	Freeze Frame
U0029-00 CAN Communication Failure (Ch1 Bus OFF)

DTC (Electric brake booster)

Electric brake booster communication check
-1. Turn the vehicle to the ON mode.

-2. Check for communication between the electric brake booster and the HDS.

Is there communication between the electric brake booster and the HDS?

YES

Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting . 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.

NO

Go to step 2.

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

-1. Turn the vehicle to the OFF (LOCK) mode with driver's door open.

-2. Wait for 3 minutes.

NOTE: Do not close the driver's door.

-3. Jump the SCS line with the HDS, and wait more than 1 minute.

-4. Disconnect the following connectors.

Electric brake booster 26P connector

PCM connector A (50P)

-5. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Electric brake booster 26P connector: disconnected
	PCM connector A (50P): disconnected
Test point 1	Electric brake booster 26P connector No. 26
Test point 2	PCM connector A (50P) No. 37

Test point 1	Electric brake booster 26P connector No. 18
Test point 2	PCM connector A (50P) No. 36

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 electric brake booster 26P connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting. If they are OK, replace the electric brake booster .

Repair an open in the wire between the electric brake booster and the PCM.