DTC U0122: Gauge Control Module Lost Communication With VSA Modulator-Control Unit (V6, Gauge Control Module with CAN gateway) (2015-17)

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 (L4), or How to Troubleshoot the Dual Clutch Transmission (DCT), or How to Troubleshoot the Brake Booster Pressure Monitoring System (With Auto Idle Stop System), or How to Troubleshoot the Fuel and Emissions Systems (V6, Without Auto Idle Stop System), or How to Troubleshoot the Fuel and Emissions Systems (V6, With Auto Idle Stop System) .

1. 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
   U3000-49 CAN Gateway Internal Failure

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

   YES 

   Go to the troubleshooting for CAN gateway system DTC (s) - Refer to: Communication Systems DTC Troubleshooting Index (V6, With CAN gateway) (2015-17) or Communication Systems DTC Troubleshooting Index (2018-19) .

   NO 

   Go to step 2.

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?

   GAUGE CONTROL MODULE (Bus A) is Not Available

   Go to step 3.

   VSA MODULATOR-CONTROL UNIT (Bus A) is Not Available

   Go to step 5. Refer to:  5

   VSA MODULATOR-CONTROL UNIT (Bus B) is Not Available

   Go to step 7. Refer to:  7

   GAUGE CONTROL MODULE and VSA MODULATOR-CONTROL UNIT are Detected

   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.

3. Open wire check (F-CAN A_H line)

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

   - 2. Disconnect the following connectors.

   Gauge control module 32P connector

   CAN gateway 24P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Gauge control module 32P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	Gauge control module 32P connector No. 27 - Refer to: Gauge Control Module Input Test (2015-17), or Gauge Control Module Input Test (2018-19)
   Test point 2	CAN gateway 24P connector No. 14

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

   Is there continuity?

   YES 

   The F-CAN A_H wire is OK. Go to step 4.

   NO 

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

4. Open wire check (F-CAN A_L line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Gauge control module 32P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	Gauge control module 32P connector No. 28 - Refer to: Gauge Control Module Input Test (2015-17), or Gauge Control Module Input Test (2018-19)
   Test point 2	CAN gateway 24P connector No. 15

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

   Is there continuity?

   YES 

   The F-CAN A_L wire is 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 DTC U0122 is not indicated the gauge control module was substituted, replace the original gauge control module .

   NO 

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

5. Open wire check (F-CAN A_H line)

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

   - 2. Disconnect the following connectors.

   VSA modulator-control unit 38P connector

   CAN gateway 24P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	VSA modulator-control unit 38P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 38 - Refer to: VSA Modulator-Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector For Inputs And Outputs (Without Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2018-19)
   Test point 2	CAN gateway 24P connector No. 14

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

   Is there continuity?

   YES 

   The F-CAN A_H wire is OK. Go to step 6.

   NO 

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

6. Open wire check (F-CAN A_L line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	VSA modulator-control unit 38P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 26 - Refer to: VSA Modulator-Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector For Inputs And Outputs (Without Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2018-19)
   Test point 2	CAN gateway 24P connector No. 15

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

   Is there continuity?

   YES 

   The F-CAN A_L wire is OK. Check for poor connections or loose terminals at the CAN gateway and the VSA modulator-control unit. Update the VSA modulator-control unit - Refer to: VSA Modulator-Control Unit Update (With SH-AWD), or VSA Modulator-Control Unit Update if it does not have the latest software, then recheck. If DTC U0122 goes away and the VSA modulator-control unit was updated, troubleshooting is complete. If DTC U0122 is still indicated, replace the VSA modulator-control unit - Refer to: VSA Modulator-Control Unit Removal and Installation (With SH-AWD), or VSA Modulator-Control Unit Removal and Installation (Without SH-AWD) .

   NO 

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

7. Open wire check (F-CAN B_H line)

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

   - 2. Disconnect the following connectors.

   VSA modulator-control unit 38P connector

   CAN gateway 24P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	VSA modulator-control unit 38P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 31 - Refer to: VSA Modulator-Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector For Inputs And Outputs (Without Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2018-19)
   Test point 2	CAN gateway 24P connector No. 11

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

   Is there continuity?

   YES 

   The F-CAN B_H wire is OK. Go to step 8.

   NO 

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

8. Open wire check (F-CAN B_L line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	VSA modulator-control unit 38P connector: disconnected
   	CAN gateway 24P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 20 - Refer to: VSA Modulator-Control Unit Connector For Inputs And Outputs (With Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector For Inputs And Outputs (Without Auto Idle Stop System) (2015-17) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2018-19)
   Test point 2	CAN gateway 24P connector No. 10

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

   Is there continuity?

   YES 

   The F-CAN B_L wire is OK. Check for poor connections or loose terminals at the CAN gateway and the VSA modulator-control unit. Update the VSA modulator-control unit - Refer to: VSA Modulator-Control Unit Update (With SH-AWD), or VSA Modulator-Control Unit Update if it does not have the latest software then recheck. If DTC U0122 goes away and the VSA modulator-control unit was updated, troubleshooting is complete. If DTC U0122 is still indicated, replace the VSA modulator-control unit - Refer to: VSA Modulator-Control Unit Removal and Installation (With SH-AWD), or VSA Modulator-Control Unit Removal and Installation (Without SH-AWD) .

   NO 

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