DTC: C0023-14

DTC C0023-14  : Brake Diag Circuit OFF Failure

NOTE: Before You Troubleshoot, Review The General Troubleshooting Information .

DTCs (VSA)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   - 2. Clear the DTC with the HDS.

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

   - 4. After the VSA indicator goes off, press the brake pedal for 3 seconds or more.

   - 5. Check for DTCs with the HDS.

   DTC Description	DTC	Freeze Frame
   Frame C0023-14 Brake Diag Circuit OFF Failure

   Is DTC C0023-14 indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   The failure is not duplicated. Go to step 5.

2. Open wire check (STOP SW line)

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

   - 2. Remove the brake light relay.

   - 3. Disconnect the following connectors.

   Brake pedal position switch 4P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake pedal position switch 4P connector: disconnected
   	Brake light relay: disconnected
   Test point 1	Brake pedal position switch 4P connector No. 1
   Test point 2	Brake light relay 5P socket No. 4

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

   Is there continuity?

   YES 

   The STOP SW wire is OK. Go to step 3.

   NO 

   Repair an open in the wire between the brake pedal position switch and the brake light relay.

3. Open wire check (BRAKE DIAG line) 1

   -1. Disconnect the following connector.

   VSA modulator-control unit 38P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake pedal position switch 4P connector: disconnected
   	Brake light relay: disconnected
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket No. 1
   Test point 2	VSA modulator-control unit 38P connector No. 5 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2016 2017 2018) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2019 2020 2019)

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

   Is there continuity?

   YES 

   The BRAKE DIAG wire is OK. Go to step 4.

   NO 

   Repair an open in the wire between the VSA modulator-control unit and the brake light relay.

4. Brake light relay check (substitution)

   -1. Substitute a known-good brake light relay.

   - 2. Reconnect the following connectors.

   Brake pedal position switch 4P connector

   VSA modulator-control unit 38P connector

   - 3. Turn the vehicle to the ON mode.

   - 4. Clear the DTC with the HDS.

   - 5. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.

   - 6. After the VSA indicator goes off, press the brake pedal for 3 seconds or more.

   - 7. Check for DTCs with the HDS.

   DTC Description	DTC	Freeze Frame
   Frame C0023-14 Brake Diag Circuit OFF Failure

   Is DTC C0023-14 indicated?

   YES 

   Go to step 9.

   NO 

   Replace the original brake light relay.

5. Open wire check (BRAKE LAMP line) 1

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

   - 2. Disconnect the following connector.

   VSA modulator-control unit 38P connector

   - 3. Connect terminals 1 and 2 with a jumper wire.

   Terminal 1	VSA modulator-control unit 38P connector No. 36 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2016 2017 2018) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2019 2020 2021)
   Terminal 2	Body ground

   - 4. Turn the vehicle to the ON mode.

   - 5. Check the brake lights without pressing the brake pedal.

   Are the brake lights on?

   YES 

   Go to step 8.

   NO 

   Go to step 6.

6. Open wire check (BRAKE LAMP line) 2

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

   - 2. Disconnect the jumper wire.

   - 3. Remove the brake light relay.

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake light relay: disconnected
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket No. 5
   Test point 2	VSA modulator-control unit 38P connector No. 36 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2016 2017 2018) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2019 2020 2021) .

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

   Is there continuity?

   YES 

   The BRAKE LAMP wire is OK. Go to step 7.

   NO 

   Repair an open in the wire between the VSA modulator-control unit and the brake light relay.

7. Open wire check (IG1 VSA (DC/DC) (With Auto Idle Stop System) line or IG1 VSA (Without Auto Idle Stop System) line)

   -1. Turn the vehicle to the ON mode.

   - 2. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Brake light relay: disconnected
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket No. 3
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   Replace the brake light relay.

   NO: With auto idle stop system

   Repair an open in the wire between the brake light relay and the No. D2 (7.5 A) fuse in the auxiliary under-dash fuse/relay box.

   NO: Without auto idle stop system

   Repair an open in the wire between the brake light relay and the No. C9 (7.5 A) fuse in the under-dash fuse/relay box.

8. Open wire check (BRAKE DIAG line) 2

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

   - 2. Disconnect the jumper wire.

   - 3. Remove the brake light relay.

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake light relay: disconnected
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket No. 1
   Test point 2	VSA modulator-control unit 38P connector No. 5 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2016 2017 2018) or VSA Modulator-Control Unit Connector for Inputs and Outputs (2019 2020 2021)

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

   Is there continuity?

   YES 

   The BRAKE DIAG wire is OK. Go to step 9.

   NO 

   Repair an open in the wire between the VSA modulator-control unit and the brake light relay.

9. VSA modulator-control unit check (substitution)

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

   - 2. Install the brake light relay (if removed).

   - 3. Reconnect the following connectors.

   VSA modulator-control unit 38P connector (if disconnected)

   - 4. Substitute a known-good VSA modulator-control unit.

   - 5. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.

   - 6. After the VSA indicator goes off, press the brake pedal for 3 seconds or more.

   - 7. Check for DTCs with the HDS.

   DTC Description	DTC	Freeze Frame

   Is DTC C0023-14 indicated?

   YES 

   Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If they are OK, replace the VSA Modulator-Control Unit. Refer to:

   Replace The VSA Modulator-Control Unit .

   NO 

   Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.