VEHICLE STABILITY CONTROL SYSTEM Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU (brake actuator assembly) is connected to the combination meter assembly via CAN communication.

If any of the following is detected, the brake warning light (red indicator) remains on:


WIRING DIAGRAM

B002DVNE01

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output.

      for LHD: Click here

      for RHD: Click here

      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output. (for LHD) B
      DTCs are output. (for RHD) C

    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    C

    INSPECT CAN COMMUNICATION SYSTEM Click here

    A

  2. CHECK IF BRAKE ACTUATOR ASSEMBLY CONNECTOR IS SECURELY CONNECTED


    1. Check if the skid control ECU (brake actuator assembly) connector is securely connected.

      OK
      The connector is securely connected.
      Result
      Proceed to
      OK
      NG

    NG

    CONNECT CONNECTOR TO BRAKE ACTUATOR ASSEMBLY CORRECTLY

    OK

  3. CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      Tester Connection Condition Specified Condition
      Battery Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    OK

  4. CHECK TERMINAL VOLTAGE (IG1 TERMINAL)


    1. B002CETC97
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Disconnect the A52 skid control ECU (brake actuator assembly) connector.

    2. Turn the engine switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A52-12 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. Turn the engine switch off.

    2. B002CA7C02
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A52-25 (GND1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  6. INSPECT BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY


    1. B002DKYC10
      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch (Brake Master Cylinder Reservoir Assembly))

      Turn the engine switch off.

    2. Remove the reservoir filler cap and strainer.

    3. Disconnect the A18 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    4. Measure the resistance according to the value(s) in the table below.

      Tech Tips

      A float is located inside the reservoir. Its position changes according to the brake fluid level.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 (+) - 2 (E) Switch OFF (Float up) 10 kΩ or higher
      1 (+) - 2 (E) Switch ON (Float down) Below 1 Ω

      Tech Tips

      If the switch condition is normal, adjust the brake fluid level to the MAX line.

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY Click here

    C

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY Click here

    A

  7. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY)


    1. Disconnect the K33 combination meter assembly connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      K33-17 (SW) - A18-1 (+) Always Below 1 Ω
      K33-17 (SW) or A18-1 (+) - Body ground Always 10 kΩ or higher
      A18-2 (E) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. READ VALUE USING GTS (BRAKE WARNING LIGHT [RED INDICATOR])


    1. Reconnect the A18 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    2. Reconnect the K33 combination meter assembly connector.

    3. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Brake Warning Light Brake warning light (red indicator) ON or OFF

      ON: Warning light on

      OFF: Warning light off

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Brake Warning Light

    4. Check the GTS display condition of the brake warning light (red indicator).

      Result
      Result Proceed to
      ON is displayed. (for LHD) A
      ON is displayed. (for RHD) B
      OFF is displayed. C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.

      Click here


    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    C

    INSPECT METER / GAUGE SYSTEM Click here