ANTI-LOCK BRAKE 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

B00273AE19

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform Test Mode (Signal Check) to acquire the rear differential lock identification information.

    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 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

  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. 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 1KD-FTV: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 1GD-FTV: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 2GD-FTV: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 2KD-FTV: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 1TR-FE: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 2TR-FE: Click here
    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY for 5L-E: Click here

    OK

  4. CHECK TERMINAL VOLTAGE (IG1 TERMINAL)


    1. B00246OC35
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Disconnect the A3 skid control ECU (brake actuator assembly) connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A3-34 (IG1) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. Turn the ignition switch off.

    2. B00246OC36
      *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
      A3-1 (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. B0024TVC01
      *a

      Component without harness connected

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

      Turn the ignition switch off.

    2. Remove the reservoir filler cap and strainer.

    3. Disconnect the A6 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 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 RESERVOIR ASSEMBLY Click here

    OK

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


    1. Disconnect the G9 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G9-16 (SW) - A6-1 (+) Always Below 1 Ω
      A6-2 (E) - Body ground Always Below 1 Ω
      G9-16 (SW) or A6-1 (+) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK (for 1GD-FTV, 1KD-FTV, 2GD-FTV, 2KD-FTV and 5L-E)
      OK (for 1TR-FE and 2TR-FE)
      NG

    OK (for 1TR-FE and 2TR-FE)

    READ VALUE USING GTS (BRAKE WARNING LIGHT) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK (for 1GD-FTV, 1KD-FTV, 2GD-FTV, 2KD-FTV and 5L-E)

  8. INSPECT VACUUM WARNING SWITCH ASSEMBLY


    1. Remove the vacuum warning switch assembly.

      Click here

    2. 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

  9. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - VACUUM WARNING SWITCH ASSEMBLY)


    1. Disconnect the A5 vacuum warning switch assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G9-9 (VCM) - A5-2 Always Below 1 Ω
      A5-1 - Body ground Always Below 1 Ω
      G9-9 (VCM) or A5-2 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. READ VALUE USING GTS (BRAKE WARNING LIGHT)


    1. Reinstall the reservoir filler cap and strainer.

    2. for 1GD-FTV, 1KD-FTV, 2GD-FTV, 2KD-FTV and 5L-E:

      Reinstall the vacuum warning switch assembly.

    3. Reconnect the A3 skid control ECU (brake actuator assembly) connector, G9 combination meter assembly connector and the A6 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    4. for 1GD-FTV, 1KD-FTV, 2GD-FTV, 2KD-FTV and 5L-E:

      Reconnect the A5 vacuum warning switch assembly connector.

    5. Connect the GTS to the DLC3.

    6. Turn the ignition switch to ON.

    7. Turn the GTS on.

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

    9. 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 warning light OFF or ON

      OFF: Warning light off

      ON: Warning light on

      		 -

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

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

      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