DTC C0023-14 (With Auto Idle Stop System) (2017 2018)

DTC C0023-14  : Brake Diag Circuit OFF Failure

NOTE:  Before you troubleshoot, review the general troubleshooting information - Refer to:

How to Troubleshoot the VSA System (2017 2018 2019 2020) .

DTC (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 to the ON mode.

   - 4. Select the BRAKE LIGHT RELAY TEST in the VSA FUNCTION TEST with the HDS.

   BRAKE LIGHT RELAY TEST

   Check for DTCs with the HDS.

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

   Is DTC C0023-14 indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

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

   How to Troubleshoot the VSA System (2017 2018 2019 2020) .

   If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

2. Brake light relay check (substitution)

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

   - 2. Substitute a known-good brake light relay. Relay and Control Unit Locations (2017 2018 2019 2020)

   - 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 to the ON mode.

   - 6. Select the BRAKE LIGHT RELAY TEST in the VSA FUNCTION TEST with the HDS.

   BRAKE LIGHT RELAY TEST

   Check for DTCs with the HDS.

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

   Is DTC C0023-14 indicated?

   YES 

   Go to step 3.

   NO 

   Replace the original brake light relay - Refer to:

   Relay and Control Unit Locations (2017 2018 2019 2020) .

3. 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. 14 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2017 2018 2019 2020)
   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 7.

   NO 

   Go to step 4.

4. 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. Relay and Control Unit Locations (2017 2018 2019 2020)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake light relay: removed
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 14 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2017 2018 2019 2020)
   Test point 2	Brake light relay 5P socket (female terminals) No. 5:

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

   Is there continuity?

   YES 

   The BRAKE LAMP wire is OK. Go to step 5.

   NO 

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

5. Open wire check (IG1 VSA (DC/DC) 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: removed
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket (female terminals) No. 3:
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The IG1 VSA (DC/DC) wire is OK. Go to step 6.

   NO 

   Repair an open in the wire between the auxiliary under-dash fuse/relay box and the brake light relay.

6. Open wire check (+B STOP (DC/DC) line)

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

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake light relay: removed
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	Brake light relay 5P socket (female terminals) No. 2:
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The +B STOP (DC/DC) wire is OK. Go to step 7.

   NO 

   Repair an open in the wire between the main under-hood fuse box and the brake light relay.

7. Open wire check (BRAKE DIAG line)

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

   - 2. Disconnect the jumper wire. (if connected)

   - 3.Remove the brake light relay.  (if installed) Relay and Control Unit Locations (2017 2018 2019 2020)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake light relay: removed
   	VSA modulator-control unit 38P connector: disconnected
   Test point 1	VSA modulator-control unit 38P connector No. 18 - Refer to: VSA Modulator-Control Unit Connector for Inputs and Outputs (2017 2018 2019 2020)
   Test point 2	Brake light relay 5P socket (female terminals) No. 1:

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

   Is there continuity?

   YES 

   The BRAKE DIAG wire is OK. 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 .

   NO 

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