ANTI-LOCK BRAKE SYSTEM(for Type B) 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 (brake actuator assembly).

  • The brake fluid level is insufficient.

  • The parking brake is applied.

  • EBD operation is not possible.

WIRING DIAGRAM

C274778E08

CAUTION / NOTICE / HINT

Note:

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

PROCEDURE

  1. CHECK CAN COMMUNICATION SYSTEM

    1. Check if CAN communication system DTCs are output.

      Click hereClick hereClick 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.

    Result

    Proceed to

    OK

    NG
    NG

    CONNECT CONNECTOR TO ACTUATOR CORRECTLY

    OK

  3. CHECK BATTERY

    1. Check the battery voltage.

      Standard Voltage

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY

    for 1ZR-FE:Click here

    for 2ZR-FE:Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)

    1. C277404C07

      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Disconnect the A124 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

      A124-34 (IG1) - Body ground

      Ignition switch ON

      11 to 14 V

      A124-34 (IG1) - A124-1 (GND1)

      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. C277404C08

      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A124-1 (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 SWITCH ASSEMBLY)

    1. Reconnect the A124 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 using the GTS.

      Click here

      Chassis > ABS/VSC/TRC > Data List

      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

      -

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Parking Brake SW

    5. Using the GTS, check the switch operation signal received when the parking brake is operated.

      OK

      The GTS 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 ASSEMBLY

    1. C230719C13

      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch (Brake Master Cylinder Reservoir Assembly))

      Turn the ignition switch off.

    2. Remove the reservoir filler cap and the strainer.

    3. Disconnect the A156 brake fluid level warning switch (brake master cylinder reservoir 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 changes according to the brake fluid level.

      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
      Tip:

      If the switch condition is normal, adjust the brake fluid level to the MAX level.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY

    Click here

    OK

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

    1. Disconnect the E46 combination meter assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E46-12 (SW) - A156-1 (+)

      Always

      Below 1 Ω

      E46-12 (SW) or A156-1 (+) - Body ground

      Always

      10 kΩ or higher

      A156-2 (E) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. INSPECT COMBINATION METER ASSEMBLY

    1. Reconnect the A156 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    2. Reconnect the E46 combination meter assembly connector.

    3. Perform an Active Test of the combination meter assembly using the GTS.

      Click hereClick here

      Body Electrical > Combination Meter > Active Test

      Tester Display

      Indicat. Lamp Brake

    4. Check the combination meter assembly.

      OK

      The brake warning light turns on or off in accordance with the Active Test operation.

      Tip:

      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

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click hereClick here

    NG

    INSPECT METER / GAUGE SYSTEM

    Click here

  10. INSPECT PARKING BRAKE SWITCH ASSEMBLY

    1. C211519C04

      *a

      Component without harness connected

      (Parking Brake Switch Assembly)

      Turn the ignition switch off.

    2. Disconnect the L18 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

      Switch ON

      (Switch pin free)

      Below 1 Ω

      1(+) - Body ground

      Switch OFF

      (Switch pin pushed in)

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE PARKING BRAKE SWITCH ASSEMBLY

    Click here

    OK

  11. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - PARKING BRAKE SWITCH ASSEMBLY)

    1. Disconnect the 3E 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

      3E-27 (PKB) - L18-1 (+)

      Always

      Below 1 Ω

      3E-27 (PKB) or L18-1 (+) - Body ground

      Always

      10 kΩ or higher
      Tip:

      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

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR