ANTI-LOCK BRAKE 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 is detected, the brake warning light remains on:

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

  • The brake fluid level is insufficient.

  • The parking brake is applied.

  • EBD operation is not possible.

WIRING DIAGRAM

C283805E03

CAUTION / NOTICE / HINT

Note:

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • When replacing the skid control ECU (brake actuator assembly), perform acceleration sensor zero point calibration and CVT oil pressure calibration (for continuously variable transaxle).

    K111:Click here

    K111F:Click here

  • When replacing the main body ECU (multiplex network body ECU), make sure to replace it with a new one.

PROCEDURE

  1. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

    1. Check if the skid control ECU (brake actuator assembly) connector is securely connected.

      OK

      The connector is securely connected.

    Result

    Proceed to

    OK

    NG
    NG

    CONNECT CONNECTOR TO ECU CORRECTLY

    OK

  2. CHECK CAN COMMUNICATION SYSTEM

    1. Check if CAN communication system DTCs are output.

      Click hereClick hereClick here

    Result

    Proceed to

    DTC is not output

    DTC is output
    DTC is output

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    DTC is not output

  3. INSPECT BATTERY

    1. Check the battery voltage.

      Standard voltage

      11 to 14 V

      Result

      Proceed to

      OK

      NG (for 2AR-FE)

      NG (for 3ZR-FE)
    NG (for 2AR-FE)

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY

    Click here

    NG (for 3ZR-FE)

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY

    Click here

    OK

  4. CHECK TERMINAL VOLTAGE (IG1 TERMINAL)

    1. C199357C66

      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Disconnect the A63 skid control ECU (brake actuator assembly) connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A63-34 (IG1) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

    1. Turn the ignition switch off.

    2. C199357C65

      *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

      Tester Connection

      Condition

      Specified Condition

      A63-1 (GND1) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

  6. READ VALUE USING GTS (PARKING BRAKE SW)

    1. Reconnect the A63 skid control ECU (brake actuator assembly) connector.

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

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

    6. According to the display on the GTS, read the Data List.

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      Parking Brake SW

      Parking brake switch assembly

      OFF or ON

      OFF: Parking brake released

      ON: Parking brake applied

      -

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Parking Brake SW

    7. Using the GTS, check the input of the switch operation when the parking brake lever is operated.

      OK

      The Techstream displays ON or OFF according to parking brake operation.

    Result

    Proceed to

    OK

    NG
    NG

    INSPECT PARKING BRAKE SWITCH ASSEMBLYClick here

    OK

  7. INSPECT BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY

    1. C235854C01

      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch [Brake Master Cylinder Reservoir Sub-assembly])

      Turn the ignition switch off.

    2. Remove the reservoir filler cap and strainer.

    3. Disconnect the A9 brake fluid level warning switch (brake master cylinder reservoir sub-assembly) connector.

    4. 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

      Switch Condition

      Specified Condition

      1 - 2

      Switch off (Float up)

      10 kΩ or higher

      Switch on (Float down)

      Below 1 Ω
      Tip:

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

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY

    Click here

    OK

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

    1. Disconnect the G16 combination meter assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      G16-12 (SW) - A9-1

      Always

      Below 1 Ω

      A9-2 - Body ground

      Always

      Below 1 Ω

      G16-12 (SW) or A9-1 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    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 G16 combination meter assembly connector and the A9 brake fluid level warning switch (brake master cylinder reservoir sub-assembly) connector.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

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

    7. According to the display on the GTS, read the Data List.

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

    Chassis > ABS/VSC/TRC > Data List

    Tester Display

    Measurement Item

    Range

    Normal Condition

    Diagnostic Note

    Brake Warning Light

    Brake warning light

    OFF or ON

    OFF: Warning light off

    ON: Warning light on

    -

    Chassis > ABS/VSC/TRC > Data List

    Tester Display

    Brake Warning Light

    Result

    Proceed to

    Display of the Data List remains OFF

    Display of the Data List remains ON
    Display of the Data List remains OFF

    INSPECT METER / GAUGE SYSTEM

    Click here

    Display of the Data List remains ON

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY

    1. Remove the parking brake switch assembly.

      Click here

    2. Inspect the parking brake switch assembly.

      Click here

    Result

    Proceed to

    OK

    NG
    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 3D 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

      3D-34 - G37-1

      Always

      Below 1 Ω

      3D-34 or G37-1 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    1. Remove the instrument panel junction block assembly.

      Click here

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

      Click here

    3. C284585C03

      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      3D-34 -A-12 (PKB)

      Always

      Below 1 Ω

      3D-34 or A-12 (PKB) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    Click here

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    Click here