DTC U0122: Gauge Control Module Lost Communication With VSA Modulator-Control Unit (Gauge Control Module) (2014)

DTC Description	DTC
U0122 Gauge control module lost communication with VSA modulator-control unit

DTC (Gauge Control Module)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems (2014-15) .

CAN gateway system DTC check

-1. 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

DTC (CAN GATEWAY)

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

YES

Go to the troubleshooting for CAN gateway system DTC (s) - Refer to: Communication Systems DTC Troubleshooting Index (2014) .

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.

Which result is indicated?

Gauge control module (Bus A) is Not Available

Go to step 3.

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

Go to step 4.

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

Go to step 5.

Gauge control module and VSA modulator-control unit are Detect

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the gauge control module, the CAN gateway, and the VSA modulator-control unit.

Open wire check (F-CAN A lines)

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

- 2. Disconnect the following connectors:

CAN gateway 24P connector

Gauge control module connector A (32P)

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

Test condition	Vehicle OFF (LOCK) mode CAN gateway 24P connector: disconnected Gauge control module connector A (32P): disconnected
Test circuit	F-CAN A_H
Test point 1	CAN gateway 24P connector No. 14 (WHT)
Test point 2	Gauge control module connector A (32P) No. 19 (WHT)

Test circuit

F-CAN A_L

Test point 1	CAN gateway 24P connector No. 15 (RED)
Test point 2	Gauge control module connector A (32P) No. 20 (RED)

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 poor connections or loose terminals at the CAN gateway and the gauge control module. Substitute a known-good gauge control module , then recheck. If the DTC U0122 goes away and the gauge control module was substituted, replace the original gauge control module .

Repair an open in F-CAN A_H or F-CAN A_L wire between the CAN gateway and the gauge control module.

Open wire check (F-CAN B lines)

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

- 2. Disconnect the following connectors:

CAN Gateway Removal and Installation (2014-15)

VSA modulator-control unit 21P connector

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

Test condition	Vehicle OFF (LOCK) mode CAN gateway 24P connector: disconnected VSA modulator-control unit 21P connector: disconnected
Test circuit	F-CAN B_H
Test point 1	CAN gateway 24P connector No. 11 (GRN)
Test point 2	VSA modulator-control unit 21P connector No. 8 (LT BLU)

Test circuit	F-CAN B_L
Test point 1	CAN gateway 24P connector No. 10 (LT GRN)
Test point 2	VSA modulator-control unit 21P connector No. 15 (LT GRN)

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

Is there continuity?

YES

The F-CAN B_H and F-CAN B_L wires are OK. Check for poor connections or loose terminals at the CAN gateway and the VSA modulator-control unit. Update the VSA modulator-control unit if it does not have the latest software, then recheck. If the DTC U0122 goes away and the VSA modulator-control unit was updated, troubleshooting is complete. If the DTC U0122 goes away and the VSA modulator-control unit was substituted, replace the original VSA modulator-control unit .

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

Open wire check (F-CAN C lines)

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

- 2. Disconnect the following connectors:

CAN gateway 24P connector

VSA modulator-control unit 21P connector

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

Test condition	Vehicle OFF (LOCK) mode CAN gateway 24P connector: disconnected VSA modulator-control unit 21P connector: disconnected
Test circuit	F-CAN C_H
Test point 1	CAN gateway 24P connector No. 9 (ORN)
Test point 2	VSA modulator-control unit 21P connector No. 9 (ORN)

Test circuit	F-CAN C_L
Test point 1	CAN gateway 24P connector No. 8 (PUR)
Test point 2	VSA modulator-control unit 21P connector No. 16 (PUR)

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

Is there continuity?

YES

The F-CAN C_H and F-CAN C_L wires are OK. Check for poor connections or loose terminals at the CAN gateway and the VSA modulator-control unit. Update the VSA modulator-control unit if it does not have the latest software, then recheck. If the DTC U0122 goes away and the VSA modulator-control unit was updated, troubleshooting is complete. If the DTC U0122 goes away and the VSA modulator-control unit was substituted, replace the original VSA modulator-control unit .

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