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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (Except HV) - Diagnostic Codes (3 Of 3), Symptom Tests & Circuit Tests >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for Gasoline Model) >> Excessive Brake Pedal Travel (No Fluid Leaks and No Air in System) [12/2019 - ] >> Procedure

Excessive Brake Pedal Travel (No Fluid Leaks and No Air in System) [12/2019 - ]: Procedure

  1. PRE-INSPECTION 
    1. Brake pedal inspection
      1. Perform a visual inspection and operate the brake pedal to check for any malfunctions.
      2. Check the brake pedal height, brake pedal free play and brake pedal reserve distance.

        Refer to ADJUSTMENT [12/2019 - 10/2022] , or refer to ADJUSTMENT [10/2022 - ]

        HINT: 

        If the brake pedal height is not within specification, confirm that there are no other malfunctions before adjusting the brake pedal height.

    2. Brake inspection
      1. Check that the disc brake pads of each wheel are installed correctly.
      2. Check that the bleeder plug and union bolt is not loose, and that there are no damaged gaskets or brake fluid leaks, for each wheel cylinder.
    3. Brake fluid leaks and air in brake line inspection
      1. Check and take a note of the fluid level in the brake master cylinder reservoir assembly.
      2. Repeatedly depress the brake pedal and confirm that the brake pedal feels normal (no air in the system, etc.).
      3. Check if the brake fluid level in the brake master cylinder reservoir assembly has changed.
      4. If the brake fluid level has decreased, check for leaks due to damaged brake lines or hoses, loose union nuts, damaged brake master cylinder sub-assembly seals, etc.
    4. Bleeding air from brake system
      1. Bleed air from the brake lines and brake actuator assembly.

        Refer to BLEEDING [12/2019 - 10/2022] , or refer to BLEEDING [10/2022 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. PERFORM ACTIVE TEST USING GTS (MOTOR RELAY) 
    1. Fully depress and hold the brake pedal.

      HINT: 

      Make sure that the brake pedal has travelled excessively before holding it depressed.

    2. Operate the motor relay using the Active Test and check if the brake pedal height changes when the pump motor is operating.

      Chassis > Brake/EPB > Active Test 

      Tester Display Measurement Item Control Range Restrict Condition Diagnostic Note
      Motor Relay ABS motor relay OFF / ON Vehicle condition: Vehicle stopped
      HINT: 
      To protect this Actuator and Solenoid, this test will only last 5 seconds.
      Refer to on-vehicle inspection for the brake actuator*
      1. *: Refer to ON-VEHICLE INSPECTION [12/2019 - ]

      Chassis > Brake/EPB > Active Test 

      Tester Display
      Motor Relay

      OK

      The brake pedal height does not change (the brake pedal travel remains excessive).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK BRAKE MASTER CYLINDER SUB-ASSEMBLY 
    1. Check that there are no brake fluid leaks and no indications of a malfunction in the brake master cylinder sub-assembly.

      OK

      There are no brake fluid leaks and no indications of a malfunction in the brake master cylinder sub-assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE MASTER CYLINDER SUB-ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

    Result: 

    OK 

    See step  4

  4. INSPECT BRAKE BOOSTER ASSEMBLY 
    1. Inspect operation of the brake booster assembly.

      Refer to ON-VEHICLE INSPECTION [12/2019 - ]

      OK

      The brake booster assembly is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    REPLACE BRAKE BOOSTER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ]