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Home >> Toyota >> 2009 >> Matrix Base, Automatic >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control/Dynamic Control System >> Vehicle Stability Control System >> DTC C1246/46 Master Cylinder Pressure Sensor Malfunction; DTC C1281/81 Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC) >> Inspection Procedure
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Inspection Procedure

NOTE: When replacing the brake actuator assembly, perform zero point calibration (See CALIBRATION  ).
  1. 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 

      STOP LIGHTS ILLUMINATION CONDITION

      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

      NG: INSPECT STOP LIGHT CIRCUIT  (See OPERATION CHECK )

      OK: Go to next step 

  2. READ VALUE USING TECHSTREAM (MASTER CYLINDER PRESSURE SENSOR) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Select Data List mode on the Techstream (See DATA LIST / ACTIVE TEST  ).

      ABS/VSC/TRAC 

      ABS/VSC/TRAC DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Master Cylinder Sensor Master cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V Reading increases when brake pedal is depressed
    4. Check that the brake fluid pressure value of the master cylinder pressure sensor observed on the Techstream changes according to brake pedal operation.

      OK: 

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

      NG: REPLACE BRAKE ACTUATOR ASSEMBLY  (See REMOVAL  )

      OK: Go to next step 

  3. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) 
    1. Select Data List mode on the Techstream (See DATA LIST / ACTIVE TEST  ).

      ABS/VSC/TRAC 

      ABS/VSC/TRAC DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Lamp SW Stop light switch / ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released
      -
    2. Check that the stop light condition observed on the Techstream changes according to brake pedal operation.

      OK: 

      When the brake pedal is depressed, the Techstream displays "ON"  .

      NG: Go to step  5

      OK: Go to next step 

  4. RECONFIRM DTC 
    1. Turn the ignition switch off.
    2. Clear the DTCs (See DTC CHECK / CLEAR  ).
    3. Start the engine.
    4. Drive the vehicle at a speed of 30 km/h (19 mph) or more and perform braking test (decelerate the vehicle by depressing the brake pedal).
    5. Check if the same DTC is recorded (See DTC CHECK / CLEAR  ).

      Result 

      DTC OUTPUT RESULT

      Result Proceed to
      DTC (C1246/46) is not output A
      DTC (C1246/46) is output B

      B: REPLACE BRAKE ACTUATOR ASSEMBLY  (See REMOVAL  )

      A: CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)  (See DIAGNOSIS SYSTEM  )

  5. INSPECT SKID CONTROL ECU (STP TERMINAL) 
    1. Turn the ignition switch off.
    2. Disconnect the skid control ECU connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      VOLTAGE SPECIFIED CONDITIONS

      Tester Connection Switch Condition Specified Condition
      A38-2 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A38-2 (STP) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

      Fig 1: Identifying Terminal STP Of A38 Connector
      G06035027Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: REPLACE BRAKE ACTUATOR ASSEMBLY  (See REMOVAL  )