Brake Warning Light Circuit

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: Brake Warning Light Circuit

Brake Warning Light Circuit

DESCRIPTION

The BRAKE warning light comes on when the brake fluid is insufficient or the parking brake is applied. The skid control ECU is connected to the combination meter via the CAN and multiplex communications.
When the DTC is normal and BRAKE warning light remains on, perform troubleshooting as indicated below.

WIRING DIAGRAM









INSPECTION PROCEDURE
NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration Initialization.

PROCEDURE

1. CHECK BRAKE FLUID LEVEL IN RESERVOIR
(a) Check that the brake fluid level is sufficient.
HINT:
- If the fluid level drops, check for a fluid leak, and repair if found.
- If no leaks exist, add and adjust fluid and then check that the trouble code is not output again.

OK:
Brake fluid level is proper.
NG -- ADD BRAKE FLUID
OK -- Continue to next step.

2. CHECK DTC FOR ABS
(a) Check if the DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.
OK -- REPAIR CIRCUIT INDICATED BY OUTPUT CODE
NG -- Continue to next step.

3. INSPECT PARKING BRAKE SWITCH ASSEMBLY




(a) Remove the parking brake switch connector.
(b) Measure the resistance of the switch.
Standard resistance:






NG -- REPLACE PARKING BRAKE SWITCH ASSEMBLY
OK -- Continue to next step.

4. CHECK WIRE HARNESS (SKID CONTROL ECU - PARKING BRAKE SWITCH)




(a) Disconnect the S9 ECU connector.
(b) Disconnect the P2 switch connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. INSPECT BRAKE FLUID LEVEL WARNING SWITCH




(a) Remove the reservoir tank cap and strainer.
(b) Disconnect the brake fluid level warning switch connector.
(c) Measure the resistance of the switch.
Standard resistance:






NG -- REPLACE BRAKE FLUID LEVEL WARNING SWITCH
OK -- Continue to next step.

6. INSPECT SKID CONTROL ECU CONNECTOR
(a) Check the skid control ECU connector's connecting condition.
OK:
The connector should be securely connected.
NG -- CONNECT CONNECTOR TO ECU CORRECTLY
OK -- Continue to next step.

7. PERFORM ACTIVE TEST USING TECHSTREAM (BRAKE WARNING LIGHT)
(a) Select the Active Test, generate a control command, and then check that the brake warning light operates.

ABS / VSC / TRAC:





OK:
The brake warning light turns on or off.
NG -- REPAIR OR REPLACE COMBINATION METER ASSEMBLY
OK -- REPLACE SKID CONTROL ECU