ELECTRONICALLY CONTROLLED BRAKE SYSTEM Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter via CAN communication.

If any of the following is detected, the brake warning light / red (malfunction) remains on:


WIRING DIAGRAM

A003S9VE05

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 DTC


    1. Check if ABS, VSC and/or electronically controlled brake system DTCs are output Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output B

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  2. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output Click here.

      Result
      Result Proceed to
      DTC is not output A
      DTC is output B

    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    A

  3. CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED


    1. Check if the skid control ECU connector is securely connected.

      OK
      The connector is securely connected.

    NG

    CONNECT CONNECTOR TO ECU CORRECTLY

    OK

  4. CHECK AUXILIARY BATTERY


    1. Check the auxiliary battery voltage.

      Standard Voltage
      11 to 14 V

    NG

    CHARGE OR REPLACE AUXILIARY BATTERY

    OK

  5. INSPECT SKID CONTROL ECU (IG1 TERMINAL)


    1. A003UTKE40
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

      Disconnect the skid control ECU 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
      A104-16 (IG1) - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)

    OK

  6. INSPECT SKID CONTROL ECU (GND TERMINAL)


    1. A003UTKE39
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

      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
      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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  7. READ VALUE USING INTELLIGENT TESTER (PARKING BRAKE SWITCH)


    1. Reconnect the skid control ECU connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Parking Brake SW Parking brake switch / ON or OFF

      ON: Parking brake applied

      OFF: Parking brake released

      		 -

    5. Using the intelligent tester, check the switch condition on the intelligent tester changes according to parking brake operation.

      OK
      The intelligent tester displays ON or OFF according to parking brake operation.

    NG

    INSPECT PARKING BRAKE SWITCH Click here

    OK

  8. INSPECT COMBINATION METER


    1. Turn the power switch off.

    2. Perform the Active Test of the combination meter (meter CPU) using the intelligent tester Click here.

    3. Check the combination meter.

      OK
      The brake warning light / red (malfunction) turns on or off in accordance with intelligent tester operation.
      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

    REPLACE COMBINATION METER Click here

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

  9. INSPECT PARKING BRAKE SWITCH


    1. A003S3DE03
      Text in Illustration
      *a

      Component without harness connected

      (Parking Brake Switch)

      Turn the power switch off.

    2. Disconnect the parking brake switch connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 (+) - Body ground

      Parking brake switch ON

      (Switch pin: free)

      		 Below 1 Ω
      1 (+) - Body ground

      Parking brake switch OFF

      (Switch pin: pushed in)

      		 10 kΩ or higher

    NG

    REPLACE PARKING BRAKE SWITCH Click here

    OK

  10. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - PARKING BRAKE SWITCH)


    1. Disconnect the main body ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2B-12 (PKB) - E12-1 (+) Always Below 1 Ω
      2B-12 (PKB) - Body ground Always 10 kΩ or higher

      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.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)