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 warning light remains on:


WIRING DIAGRAM

A01IPK3E01

INSPECTION PROCEDURE

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

    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. CHECK BATTERY


    1. Check the battery voltage.

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

    B

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    C

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    D

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY Click here

    A

  4. CHECK TERMINAL VOLTAGE (POWER SOURCE TERMINAL)


    1. A01IQ6IE01
      Text in Illustration
      *A for CVT
      *B except CVT
      *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 A78 (for CVT) or A79 (except CVT) skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage (for CVT)
      Tester Connection Condition Specified Condition
      A78-25 (+BS) - Body ground Always 11 to 14 V
      A78-25 (+BS) - A78-38 (GND1) Always 11 to 14 V
      A78-28 (IG1) - Body ground Ignition switch ON 11 to 14 V
      A78-28 (IG1) - A78-38 (GND1) Ignition switch ON 11 to 14 V
      Standard Voltage (except CVT)
      Tester Connection Condition Specified Condition
      A79-1 (+BS) - Body ground Always 11 to 14 V
      A79-1 (+BS) - A79-14 (GND1) Always 11 to 14 V
      A79-4 (IG1) - Body ground Ignition switch ON 11 to 14 V
      A79-4 (IG1) - A79-14 (GND1) Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for +BS circuit) B
      NG (w/o Stop and Start System for IG1 circuit) C
      NG (w/ Stop and Start System for IG1 circuit) D

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    D

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

    A

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A01IQ6IE02
      Text in Illustration
      *A for CVT
      *B except CVT
      *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 (for CVT)
      Tester Connection Condition Specified Condition
      A78-38 (GND1) - Body ground Always Below 1 Ω
      Standard Resistance (except CVT)
      Tester Connection Condition Specified Condition
      A79-14 (GND1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. READ VALUE USING GTS (PARKING BRAKE SWITCH ASSEMBLY)


    1. Reconnect the A78 (for CVT) or A79 (except CVT) skid control ECU (brake actuator assembly) connector.

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Select the Data List on 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 that the switch condition displayed on the GTS changes according to the parking brake operation.

      OK
      The GTS displays ON or OFF according to parking brake operation.

    NG

    INSPECT PARKING BRAKE SWITCH ASSEMBLY Click here

    OK

  7. INSPECT BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY


    1. A01IT17E02
      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 A13 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

    REPLACE BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY Click here

    OK

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


    1. Disconnect the H62 combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-1 (+) - H62-10 (SW) Always Below 1 Ω
      A13-1 (+) or H62-10 (SW) - Body ground Always 10 kΩ or higher
      A13-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. READ VALUE USING GTS (BRAKE WARNING LIGHT)


    1. Reconnect the A13 brake fluid level warning switch (brake master cylinder reservoir sub-assembly) connector.

    2. Reconnect the H62 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 warning light / ON or OFF

      ON: Warning light on

      OFF: Warning light off

      		 -

    4. 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

    B

    INSPECT METER / GAUGE SYSTEM Click here

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY


    1. Turn the ignition switch off.

    2. Remove the parking brake switch assembly Click here.

    3. Inspect the parking brake switch assembly Click here.

      OK
      The parking brake switch assembly is normal.

    NG

    REPLACE PARKING BRAKE SWITCH ASSEMBLY Click here

    OK

  11. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - PARKING BRAKE SWITCH ASSEMBLY)


    1. Disconnect the DC main body ECU (instrument panel junction block assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      DC-5 (PKB) - H17-1 Always Below 1 Ω
      DC-5 (PKB) or H17-1 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)