VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1246/46, C1281/81

DTC Code DTC Name
C1246/46 Master Cylinder Pressure Sensor Malfunction
C1281/81 Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC)

DESCRIPTION

Master cylinder pressure sensor is connected to the skid control ECU in the brake actuator assembly.

DTC C1281/81 will be cleared when the master cylinder pressure sensor sends a master cylinder pressure signal or when Test Mode ends. DTC C1281/81 is output only in Test Mode.

A01EKSLE09
DTC Code DTC Detection Condition Trouble Area
C1246/46

Any of the following is detected:


  1. The voltage of the sensor signal is out of range (below 0.129 V, above 3.29 V).

  2. The sensor supply voltage is out of range (above 5.3 V, below 4.5 V).

  3. The sensor signal offset value is out of range.

  • Stop light switch circuit

  • Master cylinder pressure sensor circuit

  • Brake actuator assembly (Master cylinder pressure sensor)
C1281/81 Detected only during Test Mode.

  • Stop light switch

  • Brake pedal load sensing switch

  • Master cylinder pressure sensor

WIRING DIAGRAM

Refer to DTC C1249/49 Click here.

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK STOP LIGHT OPERATION


    1. Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

      OK
      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

    NG

    INSPECT STOP LIGHT CIRCUIT Click here

    OK

  2. READ VALUE USING GTS (MASTER CYLINDER PRESSURE SENSOR)


    1. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Master Cylinder Sensor Master cylinder pressure sensor reading / Min.: 0 V, Max.: 5 V Brake pedal 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 GTS changes when the brake pedal is depressed.

      OK
      When the pedal is depressed, voltage displayed on the GTS increases.

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  3. READ VALUE USING GTS (STOP LIGHT SWITCH)


    1. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light 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 GTS changes when the brake pedal is depressed.

      OK
      When the brake pedal is depressed, the GTS displays "ON".

    NG

    INSPECT SKID CONTROL ECU (STP TERMINAL) Click here

    OK

  4. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Start the engine.

    4. At a speed of 30 km/h (18 mph) or more, drive the vehicle and perform braking test (decelerate the vehicle by depressing the brake pedal).

    5. Check if the same DTC is recorded Click here.

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

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  5. INSPECT SKID CONTROL ECU (STP TERMINAL)


    1. A01EIZEE52
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Brake Actuator (Skid Control ECU))

      Turn the ignition switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the skid control ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A42-30 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A42-30 (STP) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here