VEHICLE STABILITY CONTROL SYSTEM(for Vacuum Brake Booster) Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter via CAN communication.

If any of the following is detected, the brake warning light remains on:


WIRING DIAGRAM

B001D8LE12

CAUTION / NOTICE / HINT

Note

When replacing the brake actuator assembly, perform calibration Click here.

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output (for LHD without Entry and Start System: See page , for LHD with Entry and Start System: Click here.

      Result
      Result Proceed to
      DTC not output A
      DTC output for LHD without Entry and Start System B
      DTC output for LHD with Entry and Start System C

    B

    GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    C

    GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

    A

  2. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED


    1. Check if the skid control ECU connector is securely connected.

      OK
      The connector is securely connected.

    NG

    CONNECT CONNECTOR TO ECU CORRECTLY

    OK

  3. CHECK TERMINAL VOLTAGE (IG1)


    1. Disconnect the A6 skid control ECU connector.

    2. B001GNGE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A6-34 (IG1) - Body ground Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  4. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. Disconnect the A6 skid control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A6-1 (GND1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  5. READ VALUE USING INTELLIGENT TESTER (PARKING BRAKE SW)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

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

      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

      		 -

    6. Using the intelligent tester, check the input of the switch operation when the parking brake pedal is operated.

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

    NG

    INSPECT PARKING BRAKE SWITCH Click here

    OK

  6. INSPECT BRAKE FLUID LEVEL WARNING SWITCH


    1. Turn the ignition switch off.

    2. Remove the reservoir filler cap and strainer.

    3. Disconnect the A44 brake fluid level warning switch connector.

    4. B001FJUE01
      Text in Illustration
      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch)

      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.


    NG

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY Click here

    OK

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


    1. Disconnect the G6 combination meter connector.

    2. Disconnect the A44 brake fluid level warning switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G6-31 (SW) - A44-1 Always Below 1 Ω
      G6-31 (SW) - Body ground Always 10 kΩ or higher
      A44-2 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. READ VALUE USING INTELLIGENT TESTER (BRAKE WARNING LIGHT)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

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

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Brake Warning Light Brake warning light / ON or OFF OFF -

    6. When performing the Brake Warning Light Active Test, check Brake Warning Light in the Data List Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Brake Warning Light Brake warning light Warning light ON/OFF Observe the combination meter.
      Result
      Result Proceed to
      Data List Display Data List Display when Performing Active Test ON/OFF Operation
      ON Does not change between ON and OFF A
      Changes between ON and OFF B
      OFF Does not change between ON and OFF A
      Changes between ON and OFF B

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) Click here

  9. INSPECT PARKING BRAKE SWITCH


    1. Turn the ignition switch off.

    2. Disconnect the G77 parking brake switch connector.

    3. B001GG6E01
      Text in Illustration
      *a

      Component without harness connected

      (Parking Brake Switch)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - Body ground

      Parking brake switch on

      (Switch pin not pushed in)

      		 Below 1 Ω

      Parking brake switch off

      (Switch pin pushed in)

      		 10 kΩ or higher

    NG

    REPLACE PARKING BRAKE SWITCH Click here

    OK

  10. CHECK HARNESS AND CONNECTOR (PARKING BRAKE SWITCH - MAIN BODY ECU)


    1. Remove the main body ECU Click here.

    2. Disconnect the G77 parking brake switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A-12 (PKB) - G77-1 Always Below 1 Ω
      A-12 (PKB) - Body ground Always 10 kΩ or higher

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR