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VEHICLE STABILITY CONTROL SYSTEM Brake Warning Light Remains ON

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DTC Code DTC Name
  Brake Warning Light Remains ON
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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 remains on:


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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

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

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

  • Before performing this procedure, depress the brake pedal and confirm that the stop lights illuminate.

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PROCEDURE


  1. Click here

    CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output.

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      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

  2. Click here

    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

    • OKClick here
    • NG

      CONNECT CONNECTOR TO BRAKE ACTUATOR ASSEMBLY CORRECTLY

  3. Click here

    CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      Tester Connection Condition Specified Condition
      Positive (+) terminal - Negative (-) terminal Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

  4. Click here

    CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)


    1. B0066Q4C28
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Disconnect the A86 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 Condition Specified Condition
      A86-12 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

  5. Click here

    CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B0066Q4C24
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A86-25 (GND1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

  6. Click here

    INSPECT BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY


    1. B0067N8C10
      *a

      Component without harness connected

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

      Remove the reservoir filler cap and strainer.

    2. Disconnect the A17 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

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

      Tip:

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (+) - 2 (E) Brake fluid level warning switch off (Float up) 1.9 to 2.1 kΩ
      1 (+) - 2 (E) Brake fluid level warning switch on (Float down) Below 1 Ω
      Tip:

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

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY for LHD:Click here

      REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY for RHD:Click here

  7. Click here

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


    1. Disconnect the O3 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O3-17 (SW) - A17-1 (+) Always Below 1 Ω
      O3-17 (SW) or A17-1 (+) - Body ground Always 10 kΩ or higher
      A17-2 (E) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. Click here

    READ VALUE USING GTS (BRAKE WARNING LIGHT)


    1. Reconnect the A17 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    2. Reconnect the O3 combination meter assembly connector.

    3. Reconnect the A86 skid control ECU (brake actuator assembly) connector.

    4. Select the Data List on the GTS.

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

        ON: Warning light on

        OFF: Warning light off

        		 -



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




    5. Check the GTS display condition of the brake warning light.

      Result
      Result Proceed to
      ON is displayed. A
      OFF is displayed. B
      Tip:

      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.

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