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Home >> Toyota >> 2021 >> Camry LE, FWD >> Repair and Diagnosis >> Brakes >> Traction Control >> Vehicle Stability Control System (W/O Electric Parking Brake System) - Diagnostic Codes (2 Of 3) (Except Hybrid) >> VEHICLE STABILITY CONTROL SYSTEM (w/o Electric Parking Brake System) >> DTC C1246: Master Cylinder Pressure Sensor Malfunction [06/2017 - 10/2020] >> Procedure

DTC C1246: Master Cylinder Pressure Sensor Malfunction [06/2017 - 10/2020]: Procedure

  1. READ VALUE USING TECHSTREAM (BS1 VOLTAGE VALUE) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      BS1 Voltage Value +BS voltage value Min.: 0.00 V, Max.: 20.00 V - Changes in proportion to battery voltage

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display
      BS1 Voltage Value
    4. Take a note of the +BS voltage value.

      HINT: 

      The noted +BS voltage value is used in a later step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  2

  2. CHECK STOP LIGHT OPERATION 
    1. Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

      OK

      Condition Illumination Condition
      Brake pedal depressed On
      Brake pedal released Off

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 10/2020] 

    Result: 

    OK 

    See step  3

  3. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch assembly ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released      		 -

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display
      Stop Light SW
    4. Check that the stop light switch assembly display observed on the Techstream changes according to brake pedal operation.

      OK

      The Techstream displays on or off according to brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (MASTER CYLINDER PRESSURE SENSOR) 
    1. Start the engine.
    2. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Master Cylinder Sensor Master cylinder pressure sensor reading Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.20 to 0.40 V Reading increases when brake pedal is depressed

      Chassis > ABS/VSC/TRAC/EPB > Data List 

      Tester Display
      Master Cylinder Sensor
    3. Check that the brake fluid pressure value of the master cylinder pressure sensor observed on the Techstream changes when the brake pedal is depressed.

      OK

      When the brake pedal is depressed, the voltage displayed on the Techstream increases.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [06/2017 - 10/2020] 

    Result: 

    OK 

    See step  5

  5. RECONFIRM DTC 
    1. Clear the DTCs.

      Chassis > ABS/VSC/TRAC/EPB > Clear DTCs 

    2. Turn the ignition switch off.
    3. Start the engine.
    4. Drive the vehicle and depress the brake pedal several times to test the stop light circuit.
    5. Check if the same DTC is output.

      Chassis > ABS/VSC/TRAC/EPB > Trouble Codes 

      Result

      Result Proceed to
      C1246 is not output A
      C1246 is output B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2017 - 08/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2018 - 09/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2019 - 03/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2020 - 10/2020] 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [06/2017 - 10/2020] 

  6. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the ignition switch off.
      GTY765301Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control ECU (Brake Actuator Assembly))
    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

    3. Disconnect the A33 skid control ECU (brake actuator assembly) connector.
    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A33-30 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) (+BS x 0.85) to 14 V*
      A33-30 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

      HINT: 

      *: The minimum voltage value varies depending on the +BS terminal voltage value. The minimum voltage is 85% or more of the +BS terminal voltage.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [06/2017 - 10/2020] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

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