ELECTRONICALLY CONTROLLED BRAKE SYSTEM Brake Hold Standby Indicator Light Circuit

DESCRIPTION

The brake hold standby indicator light turns on if brake hold control is possible when the following conditions required for operation standby are met and the brake hold switch (integration control and panel assembly) is turned on while the power switch is on (IG).


WIRING DIAGRAM

B002H28E01

CAUTION / NOTICE / HINT

Tech Tips

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

Click here

PROCEDURE


  1. PRE-CHECK


    1. If the brake hold standby indicator light does not illuminate even though the brake hold switch (integration control and panel assembly) is pushed, check that the brake hold function operation conditions are met.


      1. The driver's door is closed.

      2. Driver's seat belt is fastened.

      3. The engine hood is closed.

      4. The back door is closed.

      5. The system is normal.

      Tech Tips

      If a malfunction occurs in one of the following systems, the brake hold operated indicator light will blink. If this occurs, perform troubleshooting on the malfunctioning system.


      • Brake system

      • Electric parking brake system

      • Hybrid control system

      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK CAN COMMUNICATION SYSTEM


    1. Check if CAN communication system DTCs are output.

      Click here

      Result
      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    A

  3. PERFORM ACTIVE TEST USING GTS (BRAKE HOLD STANDBY INDICATOR LIGHT)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the Active Test on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      BH Standby Light Brake hold standby indicator light Indicator light ON/OFF Observe combination meter

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      BH Standby Light

    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
      BH Standby Light Brake hold standby indicator light ON or OFF

      ON: Indicator light on

      OFF: Indicator light off

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      BH Standby Light

    5. Check the operating condition of the brake hold standby indicator light when operating it using the GTS.

      Result
      Result Proceed to
      Brake hold standby indicator light in the Data List does not change using the Active Test. A
      Brake hold standby indicator light in the Data List turns ON/OFF using the Active Test. 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 parts.

      Click here


    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    B

  4. INSPECT COMBINATION METER ASSEMBLY


    1. Turn the power switch off.

    2. Perform the Active Test of the combination meter assembly (meter CPU) using the GTS.

      Click here


      Body Electrical > Combination Meter > Active Test
      Tester Display
      Indicat. Brake Hold

    3. Check the combination meter assembly.

      OK
      The brake hold standby indicator light turns on or off in accordance with GTS operation.

      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

      Result
      Proceed to
      OK
      NG

    NG

    INSPECT METER / GAUGE SYSTEM Click here

    OK

  5. INSPECT INTEGRATION CONTROL AND PANEL ASSEMBLY


    1. Turn the power switch off.

    2. Remove the brake hold switch (integration control and panel assembly).

      Click here

    3. Inspect the brake hold switch (integration control and panel assembly).

      Click here

      OK
      The brake hold switch (integration control and panel assembly) operates normally.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE INTEGRATION CONTROL AND PANEL ASSEMBLY Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - INTEGRATION CONTROL AND PANEL ASSEMBLY)


    1. Disconnect the A57 skid control ECU (brake booster with master cylinder assembly) connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A57-10 (HZRI) - I35-8 (SLT1) Always Below 1 Ω
      A57-10 (HZRI) or I35-8 (SLT1) - Body ground Always 10 kΩ or higher
      I35-16 (GND1) - Body ground Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      A57-10 (HZRI) - I35-1 (SLT1) Always Below 1 Ω
      A57-10 (HZRI) or I35-1 (SLT1) - Body ground Always 10 kΩ or higher
      I35-9 (GND1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY


    1. Turn on the interior lights and check that they illuminate, and then set the switch so that the lights illuminate when the door is opened.

    2. Check that the lights illuminate when the driver door is opened.

      OK
      The interior lights illuminate when the driver door is opened.
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT LIGHTING SYSTEM Click here

    OK

  8. CHECK HARNESS AND CONNECTOR (CTY TERMINAL)


    1. B002K8EC25
      *a

      Front view of wire harness connector

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-19 (CTY) - Body ground Driver door open Below 1 V
      A57-19 (CTY) - Body ground Driver door closed Pulse generation
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CTY CIRCUIT)