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

A01W5BLE02

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information 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 (w/o Stop and Start System).

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output (See page for with Central Gateway ECU, Click here for without Central Gateway ECU).

      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output (w/ Central Gateway ECU). B
      DTCs are output (w/o Central Gateway ECU). C

    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    C

    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 BRAKE ACTUATOR ASSEMBLY CORRECTLY

    OK

  3. INSPECT BATTERY


    1. Check the battery voltage.

      Standard Voltage
      11 to 14 V
      Result
      Result Proceed to
      Proper ECM is installed. A
      Proper ECM are not installed (for 2AR-FE). B
      Proper ECM are not installed (for 2GR-FE). C
      Proper ECM are not installed (for 6AR-FSE). D

    B

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY Click here

    C

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY Click here

    D

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY Click here

    A

  4. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)


    1. A01W4G2E03
      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
      A40-12 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      Result
      Result Proceed to
      OK A
      NG (w/o Stop and Start System) B
      NG (w/ Stop and Start System) C

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    C

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

    A

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A01W4GYE02
      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
      A40-25 (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. A01W34CE09
      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 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 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) 1.9 to 2.1 kΩ
      1 (+) - 2 (E) Switch on (Float down) Below 1 Ω
      Result
      Result Proceed to
      OK (except 6AR-FSE) A
      OK (for 6AR-FSE) B
      NG (for LHD) C
      NG (for RHD) D

      Tech Tips

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


    B

    CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY) Click here

    C

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY Click here

    D

    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
      H14-17 (SW) - A27-1 (+) Always Below 1 Ω
      H14-17 (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. READ VALUE USING GTS (BRAKE WARNING LIGHT)


    1. Reinstall the reservoir filler cap and strainer.

    2. Reconnect the H14 combination meter assembly connector and the A27 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

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

    4. Connect the GTS to the DLC3.

    5. Turn the engine switch on (IG).

    6. Turn the GTS on.

    7. Select the Data List using the GTS Click here.

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

      ON: Warning light on

      OFF: Warning light off

      		 -

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

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

      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.


    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    INSPECT METER / GAUGE SYSTEM Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY


    1. A01VZS4E10
      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.


    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the B1 vacuum warning switch assembly connector.

    2. Disconnect the H14 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H14-17 (SW) - A27-1 (+) Always Below 1 Ω
      H14-17 (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

  13. INSPECT VACUUM WARNING SWITCH ASSEMBLY


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

    2. Reconnect the B1 vacuum warning switch assembly connector.

    3. Reconnect the H14 combination meter assembly connector.

    4. Inspect the vacuum warning switch assembly Click here.

      OK
      The vacuum warning switch assembly is normal.

    NG

    REPLACE VACUUM WARNING SWITCH ASSEMBLY Click here

    OK

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


    1. Disconnect the A27 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    2. Disconnect the B1 vacuum warning switch assembly connector.

    3. Disconnect the H14 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H14-23 (IND) - B1-2 (+) Always Below 1 Ω
      H14-23 (IND) or B1-2 (+) - Body ground Always 10 kΩ or higher
      B1-1 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  15. READ VALUE USING GTS (BRAKE WARNING LIGHT)


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

    2. Reconnect the B1 vacuum warning switch assembly connector.

    3. Reconnect the H14 combination meter assembly connector.

    4. Select the Data List using the GTS Click here.

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

      ON: Warning light on

      OFF: Warning light off

      		 -

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

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

      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.


    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    INSPECT METER / GAUGE SYSTEM Click here