DTC U0122-00 (Electric Parking Brake Control Unit) (2016 2017)

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2020 Acura RLX, 2019 Acura RLX, 2018 Acura RLX, 2017 Acura RLX, and 2016 Acura RLX. However, it is still accessible from the selected car via links, so may be relevant.

DTC U0122-00 : F-CAN Malfunction (Electric Parking Brake Control Unit-VSA Modulator-Control Unit)

DTC Description	DTC
U0122-00 F-CAN Malfunction (Electric Parking Brake Control Unit-VSA Modulator-Control Unit)

DTC (Electric parking brake)

CAN gateway system DTC check

-1. Turn the vehicle to the ON mode.

-2. Check for CAN gateway system DTCs with the HDS.

DTC Description	DTC
U0029-00 CAN Gateway F-CAN ch A Bus Off
U0047-00 CAN Gateway F-CAN ch B Bus Off
U0056-00 CAN Gateway F-CAN ch C Bus Off
U3000-49 CAN Gateway Internal Failure

Is DTC U0029-00, U0047-00, U0056-00, and/or U3000-49 indicated?

YES

Go to the troubleshooting for CAN gateway system DTC (s).

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

Which result is indicated?

VSA modulator-control unit (Bus B) is Not Available

Go to step 3.

VSA modulator-control unit (Bus C) is Not Available

Go to step 4.

Electric parking brake control unit is Not Available

Go to step 5.

Electric parking brake control unit and VSA modulator-control unit are Detected

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

Open wire check (F-CAN B_L, F-CAN B_H lines)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

VSA modulator-control unit 38P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	VSA modulator-control unit 38P connector: disconnected
Test circuit	F-CAN B_L
Test point 1	CAN gateway 24P connector No. 10 (GRY)
Test point 2	VSA modulator-control unit 38P connector No. 26 (GRY)

Test circuit	F-CAN B_H
Test point 1	CAN gateway 24P connector No. 11 (LT BLU)
Test point 2	VSA modulator-control unit 38P connector No. 38 (LT BLU)

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

Is there continuity?

YES

Check for loose terminals at the CAN gateway 24P connector and the VSA modulator-control unit 38P connector. If they are OK, update the VSA modulator-control unit if it does not have the latest software , then recheck. If the DTC U0122-00 goes away and the VSA modulator-control unit was updated, troubleshooting is complete. If DTC U0122-00 is indicated after the VSA modulator-control unit updated, 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 C_L, F-CAN C_H lines)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

VSA modulator-control unit 38P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	VSA modulator-control unit 38P connector: disconnected
Test circuit	F-CAN C_L

Test point 1	CAN gateway 24P connector No. 8 (PNK)
Test point 2	VSA modulator-control unit 38P connector No. 20 (PNK)

Test circuit	F-CAN C_H
Test point 1	CAN gateway 24P connector No. 9 (PUR)
Test point 2	VSA modulator-control unit 38P connector No. 31 (PUR)

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

Is there continuity?

YES

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

Open wire check (F-CAN B_L, F-CAN B_H lines)

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

-2. Disconnect the following connectors.

CAN gateway 24P connector

Electric parking brake control unit 30P connector

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

Test condition	Vehicle OFF (LOCK) mode
	CAN gateway 24P connector: disconnected
	Electric parking brake control unit 30P connector: disconnected
Test circuit	F-CAN B_L
Test point 1	CAN gateway 24P connector No. 10 (GRY)
Test point 2	Electric parking brake control unit 30P connector No. 29 (GRY)

Test circuit	F-CAN B_H
Test point 1	CAN gateway 24P connector No. 11 (LT BLU)

Test point 2

Electric parking brake control unit 30P connector No. 30 (PNK)

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

Is there continuity?

YES

The F-CAN B_L and F-CAN B_H wires are OK. Go to step 6.

Repair an open in the wire between the CAN gateway and the electric parking brake control unit.

Electric parking brake control unit check (update or substitution)

-1. Reconnect the following connectors.

CAN gateway 24P connector

Electric parking brake control unit 30P connector

-2. Update the electric parking brake control unit if it does not have the latest software . If the unit already has the latest software, substitute a known-good electric parking brake control unit .

-3. Turn the vehicle to the OFF (LOCK) mode.

-4. Start the engine, and let it idle for at least 5 seconds.

-5. Check for DTCs with the HDS.

DTC Description	DTC
U0122-00 F-CAN Malfunction (Electric Parking Brake Control Unit-VSA Modulator-Control Unit)

Is DTC U0122-00 indicated?

YES

Check for loose terminals and poor connections at the electric parking brake control unit. If the electric parking brake control unit was updated, substitute a known-good electric parking brake control unit , then retest. If the electric parking brake control unit was substituted, go to step 1.

If the electric parking brake control unit was updated, troubleshooting is complete. If the electric parking brake control unit was substituted, replace the original electric parking brake control unit .