Brake Warning Light Does Not Go Off

Detecting condition: 

• Brake warning light circuit is shorted.
• Defective sensor/connector
• Defective CAN communication

Trouble symptom: 

Brake warning light does not go off after starting the engine.

Wiring diagram: 

Parking brake/brake fluid level warning light system Refer to WIRING SYSTEM>Parking Brake/Brake Fluid Level Warning Light System .

Combination meter system Refer to WIRING SYSTEM>Combination Meter System .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK INSTALLATION OF VDCCM&H/U CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check that the VDCCM&H/U connector is inserted until it is locked by clamp.

      Is the connector firmly inserted?

      Yes  : Go to  2.

      No  : Insert the VDCCM&H/U connector until it is locked by clamp.

2. READ DTC  .

   Read the DTC of [Brake Control] using the Subaru Select Monitor. Refer to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC displayed?

   Yes  : Perform the diagnosis according to the DTC. Refer to BRAKE CONTROL (DIAGNOSTICS)>Diagnostic Trouble Code (DTC)>LIST .

   No  : Go to  3.

3. CHECK LAN SYSTEM  .

   Check the LAN system. Refer to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

   Is the check result OK?

   Yes  : Go to  4.

   No  : Perform the diagnosis for LAN system.

4. CHECK BRAKE FLUID AMOUNT  .

   Check the amount of brake fluid in the reservoir tank of master cylinder.

   Does the level of the brake fluid amount fall between the lines of "MAX" and "MIN"?

   Yes  : Go to  5.

   No  : Replenish brake fluid to the specified value.

5. CHECK BRAKE FLUID LEVEL SWITCH  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the level switch connector (B99) from master cylinder.
   3. Measure the resistance of master cylinder terminals.

      Terminals 

      No. 1 - No. 2:

      Is the resistance 1 MΩ or more?

      Yes  : Go to  6.

      No  : Replace the master cylinder. Refer to BRAKE>Master Cylinder .

6. CHECK GROUND SHORT OF HARNESS  .
   1. Disconnect the connector from VDCCM.
   2. Measure the resistance between VDCCM connector and chassis ground.

      Connector & terminal 

      (B66) No. 27 - Chassis ground:

      Is the resistance 1 MΩ or more?

      Yes  : Go to  7.

      No  : Repair the harness between VDCCM and brake fluid level switch.

7. CHECK COMBINATION METER  .

   Check the combination meter. Refer to COMBINATION METER (DIAGNOSTICS)>Basic Diagnostic Procedure .

   Is the check result OK?

   Yes  : Replace the VDCCM&H/U. Refer to VEHICLE DYNAMICS CONTROL (VDC)>VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U) .

   No  : Replace the combination meter. Refer to INSTRUMENTATION/DRIVER INFO>COMBINATION METER .