ELECTRONICALLY CONTROLLED BRAKE SYSTEM Brake Hold Operated Indicator Light Circuit

DESCRIPTION

The brake hold operated indicator light illuminates when the brake hold system is operating (vehicle stopped via brake fluid pressure hold) and turns off when the brake hold system operation is finished (brake fluid pressure decreases).

The brake hold system may not operate depending on vehicle conditions even when the system is in standby mode and the brake hold standby indicator light is illuminated.

If there is a system malfunction that causes brake hold control to be prohibited, when the vehicle is under the following conditions and the brake hold switch (integration control and panel assembly) is turned on, the brake hold operated indicator light blinks.


Tech Tips


  • When the power switch is turned off during brake hold operation, control stops.

  • If brake hold control does not operate even when the vehicle stops, depress on the brake pedal again firmly to stop the vehicle.

    If brake hold control still does not operate, confirm the conditions for brake hold control to operate.

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

PROCEDURE


  1. PRE-CHECK


    1. Check that the brake hold standby indicator light operates normally.

    2. If the brake hold operated indicator light does not illuminate although the brake hold standby indicator light is illuminated, check that the following brake hold operation (maintaining brake oil pressure) conditions are met.


      1. System is in operation standby state (brake hold operated indicator light is illuminated).

      2. Shift position is not P or R.

      3. Driver is depressing brake pedal and vehicle is fully stopped.

      4. Driver is not depressing accelerator pedal.

      5. Vehicle is not on steep decline.

      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. PERFORM ACTIVE TEST USING GTS (BRAKE HOLD OPERATED 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 Operated Light Brake hold operated indicator light Indicator light ON/OFF Observe combination meter

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      BH Operated 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 Operated Light Brake hold operated indicator light ON or OFF

      ON: Indicator light on

      OFF: Indicator light off

      		 -

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

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

      Result
      Result Proceed to
      Brake hold operated indicator light in the Data List does not change using the Active Test. A
      Brake hold operated 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.

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    A

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

    B

  3. 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. Hold

    3. Check the combination meter assembly.

      OK
      The brake hold operated 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

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    INSPECT METER / GAUGE SYSTEM Click here