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 system warning light (red indicator) remains on:


WIRING DIAGRAM

B0058X1E01

CAUTION / NOTICE / HINT

Note


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

    Click here

  • w/o Stop and Start System:

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

PROCEDURE


  1. CHECK IF SKID CONTROL ECU 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 ECU CORRECTLY

    OK

  2. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output.

      for LHD: Click here

      for RHD: Click here

      Result
      Proceed to
      DTC is not output
      DTC is output

    DTC is output

    CHECK CAN COMMUNICATION SYSTEM for LHD: Click here
    CHECK CAN COMMUNICATION SYSTEM for RHD: Click here

    DTC is not output

  3. INSPECT BATTERY


    1. Check the battery voltage.

      Standard voltage
      11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 8AR-FTS: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 3ZR-FAE: Click here

    OK

  4. CHECK TERMINAL VOLTAGE (IG1 TERMINAL)


    1. B005ABPC23
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Disconnect the A36 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
      A36-12 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V*1
      11 to 14 V*2

      • *1: w/ Stop and Start System

      • *2: w/o Stop and Start System

      Result
      Proceed to
      OK
      NG (w/ Stop and Start System)
      NG (w/o Stop and Start System)

    NG (w/ Stop and Start System)

    INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT) Click here

    NG (w/o Stop and Start System)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. Turn the engine switch off.

    2. B005ABPC24
      *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
      A36-25 (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 SUB-ASSEMBLY


    1. B0057MAC01
      *a

      Component without harness connected

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

      Turn the engine switch off.

    2. Remove the reservoir filler cap and strainer.

    3. Disconnect the A6 brake fluid level warning switch (brake master cylinder sub-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 can be changed by increasing or decreasing the level of brake fluid.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch off (Float up) 10 kΩ or higher
      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
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY for LHD: Click here
    REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY for RHD: Click here

    OK

  7. INSPECT VACUUM WARNING SWITCH ASSEMBLY


    1. Inspect the vacuum warning switch assembly.

      Click here

      OK
      The vacuum warning switch assembly is normal.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE VACUUM WARNING SWITCH ASSEMBLY Click here

    OK

  8. CHECK HARNESS AND CONNECTOR (BRAKE WARNING LIGHT CIRCUIT)


    1. Disconnect the I10 combination meter assembly connector.

    2. w/o Stop and Start System:

      Disconnect the A64 vacuum warning switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I10-17 (SW) or A6-1 (+) - Body ground Always 10 kΩ or higher
      I10-17 (SW) or A64-2 (+) - Body ground* Always 10 kΩ or higher

      • *: w/o Stop and Start System

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. READ VALUE USING GTS (BRAKE SYSTEM WARNING LIGHT (RED INDICATOR))


    1. Reinstall the reservoir filler cap and strainer.

    2. Reconnect the I10 combination meter assembly connector, A64 vacuum warning switch assembly connector and the A6 brake fluid level warning switch (brake master cylinder sub-assembly) connector.

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    7. According to the display on the GTS, read the Data List.


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

      OFF: Warning light off

      ON: Warning light on

      		 -

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

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

      Result
      Proceed to
      Display of the Data List remains OFF
      Display of the Data List remains ON

    Display of the Data List remains OFF

    INSPECT METER / GAUGE SYSTEM Click here

    Display of the Data List remains ON

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here