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

A01G7RVE02

INSPECTION PROCEDURE

Note


  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration Click here.

  • If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

  • 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 Click here.

      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are 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 ACTUATOR CORRECTLY

    OK

  3. CHECK BATTERY


    1. Check the battery voltage.

      Standard Voltage
      11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for 2AR-FE) B
      NG (for 2GR-FE) C

    B

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    C

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    A

  4. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)


    1. A01G4YLE29
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Disconnect the A40 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
      A40-34 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      A40-34 (IG1) - A40-1 (GND1) Engine switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A01G4YLE30
      Text in Illustration
      *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
      A40-1 (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 ASSEMBLY)


    1. Reconnect the A40 skid control ECU (brake actuator assembly) connector.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

    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 assembly / 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 MASTER CYLINDER RESERVOIR ASSEMBLY


    1. A01G7C1E01
      Text in Illustration
      *a

      Component without harness connected

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

      Turn the engine switch off.

    2. Remove the reservoir filler cap and the strainer.

    3. Disconnect the A27 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 changes according to the brake fluid level.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (+) - 2 (E) Switch OFF (Float up) 1.9 to 2.1 kΩ
      1 (+) - 2 (E) Switch ON (Float down) Below 1 Ω

      Tech Tips

      If the switch condition is normal, 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 RESERVOIR ASSEMBLY Click here

    C

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY Click here

    A

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


    1. Disconnect the H14 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H14-14 (SW) - A27-1 (+) Always Below 1 Ω
      H14-14 (SW) - Body ground Always 10 kΩ or higher
      A27-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. INSPECT COMBINATION METER ASSEMBLY


    1. Reconnect the H14 combination meter assembly connector.

    2. Reconnect the A27 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

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

    4. 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.


    NG

    REPLACE COMBINATION METER ASSEMBLY Click here

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY


    1. A01G7SYE03
      Text in Illustration
      *a

      Component without harness connected

      (Parking Brake Switch Assembly)

      Turn the engine switch off.

    2. Disconnect the A35 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
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE PARKING BRAKE SWITCH ASSEMBLY Click here

    C

    REPLACE PARKING BRAKE SWITCH ASSEMBLY Click here

    A

  11. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - PARKING BRAKE SWITCH ASSEMBLY)


    1. Disconnect the 3D main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-20 (PKB) - A35-1 (+) Always Below 1 Ω
      3D-20 (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.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here