VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1246/46

DTC Code DTC Name
C1246/46 Master Cylinder Pressure Sensor Malfunction

DESCRIPTION

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

A006WLZE02
DTC Code DTC Detection Condition Trouble Area
C1246/46

When any of the following is detected:


  1. The voltage of the sensor signal is out of range (below 0.12 V, higher than 3.3 V).

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

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

  4. The PMC response to PST signal is out of the threshold.

  • Stop light switch circuit

  • Master cylinder pressure sensor circuit

  • Brake actuator assembly (Master cylinder pressure sensor)

WIRING DIAGRAM

Refer to DTC C1249/49 Click here.

INSPECTION PROCEDURE

Note


  • When replacing the skid control ECU (brake actuator assembly), perform the engine variant learning Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  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
      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

    NG

    INSPECT STOP LIGHT CIRCUIT Click here

    OK

  2. READ VALUE USING INTELLIGENT TESTER (MASTER CYLINDER SENSOR)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine.

    4. Select the Data List mode on the intelligent tester 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

    5. Check that the brake fluid pressure value of the master cylinder pressure sensor observed on the intelligent tester changes when the brake pedal is depressed.

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

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  3. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW)


    1. Turn the ignition switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Select the Data List mode on the intelligent tester 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

      		 -

    4. Check that the stop light switch condition observed on the intelligent tester changes when the brake pedal is depressed.

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

    NG

    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 a braking test (decelerate the vehicle by depressing the brake pedal).

    5. Check if the same DTC is output 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

    USE SIMULATION METHOD TO CHECK Click here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. Disconnect the skid control ECU connector.

    2. A003CIYE12
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      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
      Stop light switch off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here