ANTI-LOCK BRAKE SYSTEM ABS 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 ABS warning light remains on:


Tech Tips

In some cases, the GTS cannot be used when the skid control ECU (brake actuator assembly) is abnormal.

WIRING DIAGRAM

B00455OE03

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output.


      Result
      Result Proceed to
      DTC not output A
      DTC output (w/o Toyota Safety Sense) B
      DTC output (w/ Toyota Safety Sense) C

    B
    C
    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
    OK
  3. CHECK HARNESS AND CONNECTOR (IG1 TERMINAL)


    1. B0047Z0C01
      *A for RHD
      *B for LHD
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Make sure that there is no looseness in the locking part and connecting part of the connector.

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

    3. Turn the ignition switch to ON.

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

      Standard Voltage (for RHD)
      Tester Connection Switch Condition Specified Condition
      A78-20 (IG1) - Body ground Ignition switch ON 11 to 14 V
      Standard Voltage (for LHD)
      Tester Connection Switch Condition Specified Condition
      A79-20 (IG1) - Body ground Ignition switch ON 11 to 14 V
    5. Turn the ignition switch off.

      Result
      Result Proceed to
      OK A
      NG (w/o Stop and Start System) B
      NG (w/ Stop and Start System) C

    B
    C
    A
  4. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B0045K0C01
      *A for RHD
      *B for LHD
      *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 RHD)
      Tester Connection Condition Specified Condition
      A78-13 (GND1) - Body ground Always Below 1 Ω
      Standard Resistance (for LHD)
      Tester Connection Condition Specified Condition
      A79-13 (GND1) - Body ground Always Below 1 Ω
    2. Reconnect the skid control ECU (brake actuator assembly) connector.


    NG
    OK
  5. READ VALUE USING GTS (ABS WARNING LIGHT)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

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

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      ABS Warning Light ABS warning light / OFF or ON

      OFF: Warning light off

      ON: Warning light on

      -
    6. When performing the ABS Warning Light Active Test, check ABS Warning Light in the Data List.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      ABS Warning Light ABS warning light Warning light ON/OFF Observe the combination meter.
      Result
      Result Proceed to
      Data List Display Data List Display when Performing Active Test ON/OFF Operation
      ON Changes between ON and OFF A
      Does not change between ON and OFF (for LHD) B
      Does not change between ON and OFF (for RHD) C
      OFF Changes between ON and OFF A
      Does not change between ON and OFF (for LHD) B
      Does not change between ON and OFF (for RHD) C

    A
    B
    C