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 conditions is detected, the brake system warning light (red indicator) remains on:


WIRING DIAGRAM

A004SPYE02

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration 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
      DTCs are not output. A
      DTCs are output. B

    B
    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
    OK
  3. CHECK BATTERY


    1. Check the battery voltage.

      Standard voltage
      11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for 1WW) B
      NG (for 2WW) C

    B
    C
    A
  4. CHECK TERMINAL VOLTAGE (POWER SOURCE TERMINAL)


    1. A004NMFE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Make sure that there is no looseness at the locking part and the connecting part of the connector.

    2. Disconnect the A84 skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A84-1 (+BS) - Body ground Always 11 to 14 V
      A84-1 (+BS) - A84-14 (GND1) Always 11 to 14 V
      A84-4 (IG1) - Body ground Ignition switch ON 11 to 14 V
      A84-4 (IG1) - A84-14 (GND1) Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for +BS circuit) B
      NG (for IG1 circuit) C

    B
    C
    A
  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A004NS0E01
      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
      A84-14 (GND1) - Body ground Always Below 1 Ω

    NG
    OK
  6. INSPECT BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY


    1. A004NRUE04
      Text in Illustration
      *a

      Component without harness connected

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

      *b for LHD
      *c for RHD

      Remove the reservoir filler cap and strainer.

    2. Disconnect the A10 brake fluid level warning switch (brake master cylinder reservoir sub-assembly) connector.

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


    NG
    OK
  7. CHECK HARNESS AND CONNECTOR (BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY - COMBINATION METER ASSEMBLY AND BODY GROUND)


    1. Disconnect the D66 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A10-1 (+) - D66-12 (SW) Always Below 1 Ω
      A10-1 (+) or D66-12 (SW) - Body ground Always 10 kΩ or higher
      A10-2 (E) - Body ground Always Below 1 Ω

    NG
    OK
  8. READ VALUE USING GTS (BRAKE SYSTEM WARNING LIGHT (RED INDICATOR))


    1. Reconnect the A10 brake fluid level warning switch (brake master cylinder reservoir sub-assembly) connector.

    2. Reconnect the D66 combination meter assembly connector.

    3. Select the Data List on the GTS Click here.

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

      ON: Warning light on

      OFF: Warning light off

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

      Result
      Result Proceed to
      Display of the Data List remains ON. A
      Display of the Data List remains OFF. B

    A
    B