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 remains on:


WIRING DIAGRAM

B008BCAE03

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform VSC sensor neutral memorization Click here.

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

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if a CAN communication system DTC is output Click here.

      Result
      Result Proceed to
      DTC is not output. A
      DTC is output. B

    B

    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.

    NG

    CONNECT CONNECTOR TO ECU CORRECTLY

    OK

  3. CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      11 to 14 V

    NG

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. B008BC4E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A5-25 (+BS) - Body ground Always 11 to 14 V
      A5-25 (+BS) - A5-38 (GND1) Always 11 to 14 V
      A5-28 (IG1) - Body ground Ignition switch ON 11 to 14 V
      A5-28 (IG1) - A5-38 (GND1) Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B008BD3E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A5-38 (GND1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  6. READ VALUE USING GTS (PARKING BRAKE SWITCH)


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

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Select the Data List using the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Parking Brake SW Parking brake switch / ON or OFF

      ON: Parking brake applied

      OFF: Parking brake released

      		 -

    5. Using the GTS, check the switch operation signal received when the parking brake is operated.

      OK
      When the parking brake is operated, the display changes as shown above.

    NG

    INSPECT PARKING BRAKE SWITCH ASSEMBLY Click here

    OK

  7. INSPECT BRAKE FLUID LEVEL WARNING SWITCH


    1. B008BHME01
      Text in Illustration
      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch (Brake Master Cylinder Sub-assembly))

      Turn the ignition switch off.

    2. Remove the reservoir filler cap and the strainer.

    3. Disconnect the brake fluid level warning switch 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 Condition Specified Condition
      1 - 2 Switch OFF (Float up) 1.9 to 2.1 kΩ
      1 - 2 Switch ON (Float down) Below 1 Ω

      Tech Tips

      If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.

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

    B

    REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY Click here

    C

    REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY Click here

    A

  8. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE FLUID LEVEL WARNING SWITCH)


    1. Disconnect the combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D7-17 (LBL) - A59-1 Always Below 1 Ω
      D7-17 (LBL) - Body ground Always 10 kΩ or higher
      A59-2 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. INSPECT COMBINATION METER ASSEMBLY


    1. Reconnect the combination meter assembly connector and the brake fluid level warning switch connector.

    2. Perform an Active Test of the combination meter assembly (meter CPU) using the GTS Click here.

    3. Check the combination meter assembly.

      OK
      The brake warning light turns on or off in accordance with the Active Test operation.

      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.


    OK

    REPLACE SKID CONTROL ECU Click here

    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY


    1. B008BGVE14
      Text in Illustration
      *a

      Component without harness connected

      (Parking Brake Switch Assembly)

      Turn the ignition switch off.

    2. Disconnect the parking brake switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 - Body ground

      Parking brake switch ON

      (Switch pin free)

      		 Below 1 Ω
      1 - Body ground

      Parking brake switch OFF

      (Switch pin pushed in)

      		 10 kΩ or higher

    NG

    REPLACE PARKING BRAKE SWITCH ASSEMBLY Click here

    OK

  11. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - PARKING BRAKE SWITCH ASSEMBLY)


    1. Disconnect the instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3B-24 - D31-1 Always Below 1 Ω
      3B-24 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

    2. Remove the main body ECU (network gateway ECU) from the instrument panel junction block assembly Click here.

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

      B008BCBE01
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      MB-14 (PKB) - 3B-24 Always Below 1 Ω
      MB-14 (PKB) - Body ground Always 10 kΩ or higher

      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.


    OK

    REPLACE MAIN BODY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here