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Home >> Lexus >> 2023 >> LX 600 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (W/O Canister Pump Module) - Circuit Tests (2 Of 2) & Symptom Tests >> SFI SYSTEM (w/o Canister Pump Module) >> Brake Override System [12/2021 - ] >> Procedure

Brake Override System [12/2021 - ]: Procedure

  1. CHECK DTC OUTPUT 
    1. Enter the following menus: System Select / Health Check.
    2. Check the DTCs.

      Result

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

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2021 - ] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (MASTER CYLINDER SENSOR 1) 
    1. Start the engine.
    2. Read the value displayed on the GTS.

      Chassis > Brake/EPB > Data List 

      Tester Display
      Master Cylinder Sensor 1

      Standard

      -1.00 to 0.00 MPa (Brake pedal released).

    3. Check that the brake fluid pressure value of the "Master Cylinder Pressure" observed on the GTS changes when the brake pedal is depressed.

      OK

      When the pedal is depressed, the pressure displayed on the GTS increases.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CHECK BRAKE ACTUATOR ASSEMBLY 

    Result: 

    OK 

    See step  3

  3. READ VALUE USING GTS (STOP LIGHT SW) 
    1. Check the Data List indication when the brake pedal is depressed and released.

      Powertrain > Engine > Data List 

      Tester Display
      Stop Light SW

      OK

      GTS Display Condition Specified Condition
      Stop Light SW Brake pedal released OFF
      Brake pedal depressed ON

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT STOP LIGHT SWITCH ASSEMBLY. Refer to  ON-VEHICLE INSPECTION [12/2021 - ] 

    Result: 

    OK 

    See step  4

  4. INSPECT BRAKE PEDAL 
    1. Inspect and adjust the brake pedal.

      Refer to ADJUSTMENT [12/2021 - ]

      HINT: 

      If the stop light switch turns ON too late, the start of brake override system control may be delayed; if it turns ON too soon, brake override system control may begin too early, so conduct inspection of the brake pedal and stop light switch assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE BRAKE PEDAL SUPPORT ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    OK 

    See step  5

  5. READ VALUE USING GTS (ACCELERATOR PEDAL POSITION SENSOR) 
    1. Read the value displayed on the GTS.

      Powertrain > Engine > Data List 

      Tester Display
      Accelerator Position Sensor No. 1 Voltage %
      Accelerator Position Sensor No. 2 Voltage %

      OK

      GTS Display Condition Specified Condition
      Accelerator Position Sensor No. 1 Voltage % Accelerator Pedal Released → Depressed → Released Values smoothly change following accelerator pedal operation
      Accelerator Position Sensor No. 2 Voltage %

      HINT: 

      For numerical values of Accelerator Position Sensor No. 1 Voltage % and Accelerator Position Sensor No. 2 Voltage %, refer to the Data List.

      Refer to DATA LIST / ACTIVE TEST [12/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ACCELERATOR PEDAL (WITH SENSOR) ROD ASSEMBLY. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    OK 

    See step  6

  6. READ VALUE USING GTS (VEHICLE SPEED) 
    1. Start the engine.
    2. Read the value displayed on the GTS.

      Powertrain > Engine > Data List 

      Tester Display
      Vehicle Speed

      Standard

      GTS Display Condition Specified Condition
      Vehicle Speed Vehicle stopped, engine running 0 km/h (0 mph)
      Vehicle being driven at constant speed between 16.1 to 64.4 km/h (10 to 40 mph) No large fluctuations when driving at a constant speed
      WARNING:

      When performing a drive test, obey all speed limits and traffic laws.

      HINT: 

      Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO METER / GAUGE SYSTEM (SPEED SIGNAL CIRCUIT). Refer to  Speed Signal Circuit [12/2021 - ] 

    Result: 

    OK 

    See step  7

  7. READ VALUE USING GTS (FR, FL, RR, RL WHEEL SPEED) 
    1. Start the engine.
    2. Read the value displayed on the GTS.

      Chassis > Brake/EPB > Data List 

      Tester Display
      FR Wheel Speed
      FL Wheel Speed
      RR Wheel Speed
      RL Wheel Speed

      Standard

      GTS Display Condition Specified Condition
      FR Wheel Speed
      FL Wheel Speed
      RR Wheel Speed
      RL Wheel Speed      		 Vehicle stopped, engine running 0 km/h (0 mph)
      Vehicle being driven at constant speed between 16.1 to 64.4 km/h (10 to 40 mph) No large fluctuations when driving at a constant speed
      WARNING:

      When performing a drive test, obey all speed limits and traffic laws.

      HINT: 

      Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    INSPECT FRONT OR REAR SPEED SENSOR 

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