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Home >> Toyota >> 2009 >> Sequoia Platinum, 5.7 W >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control/Dynamic Control System >> Vehicle Stability Control System >> DTC C1267/28 Brake Pedal Load Sensing Switch >> Inspection Procedure
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Inspection Procedure

NOTE: When replacing the VSC actuator assembly, perform zero point calibration (See CALIBRATION  ).
  1. CHECK TERMINAL VOLTAGE (BOOSTER PEDAL MICRO SWITCH) 
    1. Disconnect A20 booster connector.
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A20-5 (STS) - Body ground Ignition switch ON Approximately 12 V

    NG:  Go to step  3

    Fig 1: Identifying A20 Booster Connector Terminal
    G05649539Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  2. INSPECT BOOSTER PEDAL MICRO SWITCH 
    Fig 2: Brake Pedal Function Diagram
    G05649540Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. When using an oscilloscope:
      1. Connect the oscilloscope between terminals 1 (PSNO) and 5 (STS), 2 (PSNC) and 5 (STS) of the brake booster with connector being connected.
      2. Turn the ignition switch to ON.
      3. Check the signal waveform while the brake pedal is depressed and released.

        OK: Signal waveform changes as shown in the illustration. 

    2. When not using an oscilloscope:
      1. Disconnect the A20 booster connector.
      2. Turn the ignition switch to ON.
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage 

        VOLTAGE SPECIFICATION

        Tester Connection Condition Specified Condition
        A20-2 (PSNC) - A20-5 (STS) Brake pedal is depressed 6 V
        A20-1 (PSNO) - A20-5 (STS) Brake pedal is released

    NG: REPLACE BRAKE BOOSTER ASSEMBLY 

    Fig 3: Identifying A20 Booster Connector Terminal
    G05649541Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (BOOSTER PEDAL MICRO SWITCH - SKID CONTROL ECU) 
    1. Confirm that the skid control ECU connector and brake booster connector are properly connected.
    2. Disconnect the A19 ECU connector.
    3. Disconnect the A20 booster connector.
    4. Inspect both the connector case and the terminal for deformation and corrosion.

      OK: No deformation or corrosion. 

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

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Condition
      A19-24 (PSNO) - A20-1 (PSNO) Always Below 1 Ω
      A19-24 (PSNO) - Body ground Always 10 kΩ or higher
      A19-25 (PSNC) - A20-2 (PSNC) Always Below 1 Ω
      A19-25 (PSNC) - Body ground Always 10 kΩ or higher
      A19-27 (STS) - A20-5 (STS) Always Below 1 Ω
      A19-27 (STS) - Body ground Always 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 4: Identifying A19 ECU Connector Terminal And A20 Booster Connector Terminal
    G05649542Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE VSC ACTUATOR ASSEMBLY  (See REMOVAL  )

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