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 Ref. to WIRING SYSTEM>PARKING BRAKE/BRAKE FLUID LEVEL WARNING LIGHT SYSTEM .

Combination meter system Ref. to WIRING SYSTEM>COMBINATION METER SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

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

   Is the connector firmly inserted?

   Yes  : Go to  2.

   No  : Insert the VDC control module -& H/U connector until it is locked by clamp.

2. READ DTC  .

   Read the DTC using Subaru Select Monitor. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC displayed?

   Yes  : Perform the diagnosis according to the DTC. Ref. to BRAKE CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No  : Go to  3.

3. CHECK LAN SYSTEM  .

   Check the LAN system. Ref. 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 (B16) 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. Ref. to BRAKE>MASTER CYLINDER .

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

   Connector & terminal 

   (B310) No. 27 - Chassis ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  7.

   No  : Repair the harness between VDC control module and brake fluid level switch.

7. CHECK COMBINATION METER  .

   Check the combination meter. Ref. to INSTRUMENTATION/DRIVER INFO>COMBINATION METER SYSTEM>OPERATION>SELF-DIAGNOSIS DISPLAY MODE .

   Is the check result OK?

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

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