DTC U0122: Power Control Unit Lost Communication With VSA Modulator-Control Unit (VSA Message) (V6, Keyless Access Power Control Unit with CAN gateway) (2015-17)

DTC (Power Control Unit)

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?

   KEYLESS ACCESS/TPMS CONTROL UNIT (Bus B) 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

   KEYLESS ACCESS/TPMS CONTROL UNIT 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 keyless access/TPMS control unit, the CAN gateway, and the VSA modulator-control unit.

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

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

   - 2. Disconnect the following connectors.

   CAN gateway 24P connector

   Keyless access/TPMS control unit connector C (20P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	Keyless access/TPMS control unit connector C (20P): disconnected
   Test point 1	CAN gateway 24P connector No. 11
   Test point 2	Keyless access/TPMS control unit connector C (20P) No. 2

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

   Is there continuity?

   YES 

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

   NO 

   Repair an open in the F-CAN B_H wire between the keyless access/TPMS control unit and the CAN gateway.

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

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

   Test condition	Vehicle OFF (LOCK) mode
   	CAN gateway 24P connector: disconnected
   	Keyless access/TPMS control unit connector C (20P): disconnected
   Test point 1	CAN gateway 24P connector No. 10
   Test point 2	Keyless access/TPMS control unit connector C (20P) No. 12

   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 keyless access/TPMS control unit. Substitute a good-known keyless access/TPMS control unit , then recheck. If DTC U0122 is not indicated the keyless access/TPMS control unit was substituted, replace the original keyless access/TPMS control unit .

   NO 

   Repair an open in the F-CAN B_L wire between the keyless access/TPMS control unit 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.

   CAN gateway 24P connector

   VSA modulator-control unit connector (38P)

   - 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 connector (38P): disconnected
   Test point 1	CAN gateway 24P connector No. 14
   Test point 2	VSA modulator-control unit connector (38P) 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)

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

   Is there continuity?

   YES 

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

   NO 

   Repair an open in the F-CAN B_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
   	CAN gateway 24P connector: disconnected
   	VSA modulator-control unit connector (38P): disconnected
   Test point 1	CAN gateway 24P connector No. 15
   Test point 2	VSA modulator-control unit connector (38P) 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)

   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 (Without SH-AWD) 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.

   CAN gateway 24P connector

   VSA modulator-control unit connector (38P)

   - 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 connector (38P): disconnected
   Test point 1	CAN gateway 24P connector No. 11
   Test point 2	VSA modulator-control unit connector (38P) 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)

   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
   	CAN gateway 24P connector: disconnected
   	VSA modulator-control unit connector (38P): disconnected
   Test point 1	CAN gateway 24P connector No. 10
   Test point 2	VSA modulator-control unit connector (38P) 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)

   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 (Without SH-AWD) 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.