ELECTRONICALLY CONTROLLED BRAKE SYSTEM ABS Warning Light Remains ON

DTC Code DTC Name
ABS Warning Light Remains ON

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) is connected to the combination meter assembly via CAN communication.

If any of the following is detected, the ABS warning light remains on:

  • The skid control ECU (brake booster with master cylinder assembly) connector is disconnected from the brake booster with master cylinder assembly.

  • There is a malfunction in the skid control ECU (brake booster with master cylinder assembly) internal circuit.

  • There is an open in the wire harness between the combination meter assembly and the skid control ECU (brake booster with master cylinder assembly).

  • The ABS control system is defective.

Tip:

In some cases, the GTS cannot be used when the skid control ECU (brake booster with master cylinder assembly) is malfunctioning.

WIRING DIAGRAM

C270943E23

CAUTION / NOTICE / HINT

Note:

  • When replacing the skid control ECU (brake booster with master cylinder assembly), perform initialization and calibration of the linear solenoid valve.

    Click here

  • 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.

      for LHD:Click hereClick hereClick here

      for RHD:Click hereClick hereClick here

    Result

    Result

    Proceed to

    DTCs are not output.

    A

    DTCs are output.

    B
    B

    INSPECT CAN COMMUNICATION SYSTEM

    for LHD:Click here

    for RHD:Click here

    A

  2. CHECK IF BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CONNECTOR IS SECURELY CONNECTED

    1. Check if the skid control ECU (brake booster with master cylinder assembly) connector is securely connected.

      OK

      The connector is securely connected.

    Result

    Proceed to

    OK

    NG
    NG

    CONNECT CONNECTOR TO BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CORRECTLY

    OK

  3. CHECK AUXILIARY BATTERY

    1. Check the auxiliary battery voltage.

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      Auxiliary battery

      Power switch on (IG)

      11 to 14 V

      Auxiliary battery

      Power switch on (READY)

      11 to 15.5 V

    Result

    Proceed to

    OK

    NG
    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  4. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)

    1. C316493C37

      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Disconnect the A110 skid control ECU (brake booster with master cylinder assembly) connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A110-16 (IG1) - Body ground

      Power switch on (IG)

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (GND TERMINAL)

    1. C316493C33

      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

      Turn the power switch off.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A110-28 (GND) - Body ground

      Always

      Below 1 Ω

      A110-27 (GND2) - Body ground

      Always

      Below 1 Ω

      A110-26 (GND3) - Body ground

      Always

      Below 1 Ω

      A110-25 (GND4) - Body ground

      Always

      Below 1 Ω

      A110-24 (GND5) - Body ground

      Always

      Below 1 Ω

      A110-23 (GND6) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  6. READ VALUE USING GTS (ABS WARNING LIGHT)

    1. Reconnect the A110 skid control ECU (brake booster with master cylinder assembly) connector.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the GTS.

      Click here

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Measurement Item

      Range

      Normal Condition

      Diagnostic Note

      ABS Warning Light

      ABS warning light

      ON or OFF

      ON: Warning light on

      OFF: Warning light off

      -

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      ABS Warning Light

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

      Result

      Result

      Proceed to

      Display of the Data List remains OFF.

      A

      Display of the Data List remains ON.

      B
    A

    INSPECT METER / GAUGE SYSTEM

    Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

    for LHD:Click here

    for RHD:Click here