Honda HR-V: DTC Troubleshooting 58-12: Brake Diag Circuit ON Failure

NOTE: Before you troubleshoot, review the general troubleshooting information.

1. Brake light relay relay check:

1. Turn the vehicle to the OFF (LOCK) mode.
2. Check the brake lights without pressing the brake pedal.

Are the brake lights on?

YES

Replace the brake light relay.

NO

Go to step 2.

2. Shorted wire check (BRK LAMP line) 1:

1. Turn the vehicle to the ON mode.
2. Check the brake lights without pressing the brake pedal.

Are the brake lights on?

YES

Go to step 3.

NO

The BRK LAMP wire is OK. Go to step 4.

3. Shorted wire check (BRK LAMP line) 2:

1. Turn the vehicle to the OFF (LOCK) mode.
2. Disconnect the following connector.

VSA modulator-control unit 21P connector

3. Turn the vehicle to the ON mode.
4. Check the brake lights without pressing the brake pedal.

Are the brake lights on?

YES

Repair a short to body ground in the BRK LANP wire between the VSA modulator-control unit 21P connector and the brake light relay in the auxiliary under-hood relay box A.

NO

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

4. Problem verification:

1. Clear the DTC with the HDS.
2. Turn the vehicle to the OFF (LOCK) mode, then to the ON mode.
3. Press the brake pedal for 3 seconds or more.
4. Check for DTCs with the HDS.

Is DTC 58-12 indicated?

YES

The failure is duplicated. Go to step 5.

NO

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

5. Open wire check (BRK DIAG line):

1. Turn the vehicle to the OFF (LOCK) mode.
2. Short the SCS line with the HDS.

NOTE: Always short the SCS line with the HDS before removing PCM connector(s).

3. Disconnect the following connectors.

PCM connector A (51P)

Brake pedal position switch 4P connector

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

Is there continuity?

YES

The BRK DIAG wire is OK. Go to step 6.

NO

Repair an open in the BRK DIAG wire between the PCM and the brake pedal position switch.

6. PCM check (update or substitution):

1. Reconnect the following connectors.

PCM connector A (51P)

Brake pedal position switch 4P connector

2. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
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. Press the brake pedal for 3 seconds or more.
7. Check for DTCs with the HDS.

Is DTC 58-12 indicated?

YES

Go to step 7.

NO

If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM.

7. VSA modulator-control unit check (update):

1. Turn the vehicle to the OFF (LOCK) mode.
2. Reconnect the following connector.

VSA modulator-control unit 21P connector (if disconnected)

3. Update the VSA modulator-control unit if it does not have the latest software.
4. Turn the vehicle to the OFF (LOCK) mode, then to the ON mode.
5. Press the brake pedal for 3 seconds or more.
6. Check for DTCs with the HDS.

Is DTC 58-12 indicated?

YES

Check for loose terminals in the VSA modulator-control unit 21P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit.

NO

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

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