VEHICLE STABILITY CONTROL SYSTEM Brake Warning Light Remains ON

DTC Code DTC Name
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:

  • The skid control ECU (brake actuator assembly) connector is disconnected from the skid control ECU.

  • The brake fluid level is insufficient.

  • The parking brake is applied.

  • EBD operation is not possible.

WIRING DIAGRAM

C323090E02

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

    Click here

    INSPECT CAN COMMUNICATION SYSTEM

    (Click here)

  2. CHECK IF BRAKE ACTUATOR ASSEMBLY CONNECTOR IS SECURELY CONNECTED

    Click here

    CONNECT CONNECTOR TO BRAKE ACTUATOR ASSEMBLY CORRECTLY

  3. CHECK BATTERY

    Click here

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY

    (Click here)

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY

    (Click here)

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY

    (Click here)

  4. CHECK TERMINAL VOLTAGE (POWER SOURCE TERMINAL)

    Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    INSPECT STOP AND START SYSTEM (BACKUP BOOST CONVERTER CIRCUIT)

    (Click here)

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

    Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

  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).

      Table 1. 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.

    INSPECT PARKING BRAKE SWITCH ASSEMBLYClick here

  7. INSPECT BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY

    1. C199794E02

      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.

      Tip:

      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
      Table 2. 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
      Tip:

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

    REPLACE BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY

    (Click here)

  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

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  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).

      Table 3. 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

    REPLACE BRAKE ACTUATOR ASSEMBLY

    (Click here)

    INSPECT METER / GAUGE SYSTEM

    (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.

    REPLACE PARKING BRAKE SWITCH ASSEMBLY

    (Click here)

  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

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    REPAIR OR REPLACE HARNESS OR CONNECTOR