ELECTRONICALLY CONTROLLED BRAKE SYSTEM Skid Control Buzzer Circuit

DESCRIPTION

The skid control buzzer sounds intermittently to warn the driver when the accumulator pressure is abnormally low. This buzzer also sounds intermittently when VSC is operating.

Tech Tips

The skid control buzzer may sound when the accumulator pressure drops due to frequent braking Click here.

WIRING DIAGRAM

A003SB2E06

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK BUZZER OPERATION


    1. Confirm problem symptoms of the skid control buzzer according to the customer problem analysis.

      Tech Tips

      If the buzzer stopped after sounding continuously, a temporary drop in accumulator pressure is the suspected cause.

      Result
      Result Proceed to
      Buzzer does not sound A
      Buzzer sounds continuously B

    B

    INSPECT SKID CONTROL ECU Click here

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SKID CONTROL BUZZER)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the Active Test on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Buzzer Skid control buzzer Buzzer ON/OFF Buzzer can be heard

    4. Check that the buzzer sounds/stops when turning the skid control buzzer on/off using the intelligent tester.

      Result
      Result Proceed to
      Buzzer does not sound A
      Buzzer sounds/stops B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.


    B

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

  3. INSPECT SKID CONTROL BUZZER (POWER SOURCE TERMINAL)


    1. A003S0HE15
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control Buzzer)

      Turn the power switch off.

    2. Disconnect the skid control buzzer connector.

    3. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      E114-2 (IG1) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  4. INSPECT SKID CONTROL BUZZER


    1. A003SGUE13
      Text in Illustration
      *a

      Component without harness connected

      (Skid Control Buzzer)

      Turn the power switch off.

    2. Connect a negative (-) lead from the battery to terminal 1, and a positive (+) lead to terminal 2 of the skid control buzzer, and then check that the buzzer sounds.

      OK
      The skid control buzzer sounds.

    NG

    REPLACE SKID CONTROL BUZZER Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - SKID CONTROL BUZZER)


    1. Disconnect the skid control ECU connector 2 minutes after the power switch is turned off.

      Tech Tips

      Do not open/close the driver door within 2 minutes of the power switch being turned off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A104-13 (BZ) - E114-1 (BZ) Always Below 1 Ω
      A104-13 (BZ) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT SKID CONTROL ECU (GND TERMINAL)


    1. A003UTKE39
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A104-28 (GND) - Body ground Always Below 1 Ω
      A104-27 (GND2) - Body ground Always Below 1 Ω
      A104-26 (GND3) - Body ground Always Below 1 Ω
      A104-25 (GND4) - Body ground Always Below 1 Ω
      A104-24 (GND5) - Body ground Always Below 1 Ω
      A104-23 (GND6) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.


    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

  7. INSPECT SKID CONTROL ECU


    1. Disconnect the skid control ECU connector.

    2. Check skid control buzzer operation.

      Result
      Result Proceed to
      Buzzer stops (for LHD) A
      Buzzer stops (for RHD) B
      Buzzer sounds continuously C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.


    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE SKID CONTROL BUZZER Click here

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

  8. REPLACE SKID CONTROL BUZZER


    1. Reconnect the skid control ECU connector.

    2. Replace the skid control buzzer Click here.

    3. Check skid control buzzer operation.

      Result
      Result Proceed to
      Buzzer stops A
      Buzzer sounds continuously B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.


    B

    CHECK IF CONNECTOR IS SECURELY CONNECTED Click here

    A

    END

  9. CHECK IF CONNECTOR IS SECURELY CONNECTED


    1. Gently jiggle the connectors and wire harnesses and check skid control buzzer operation.

      Result
      Result Proceed to
      Buzzer stops A
      Buzzer sounds continuously B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part Click here.


    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    END