VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1246

DTC Code DTC Name
C1246 Master Cylinder Pressure Sensor Malfunction

DESCRIPTION

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

A002NY1E63
DTC No. DTC Detection Condition Trouble Area
C1246

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. An abnormality is detected in the skid control ECU internal sensor test.

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

  • Stop light switch assembly circuit

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor (brake actuator assembly)

WIRING DIAGRAM

Refer to DTC C1380 Click here.

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration 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 LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Click here

    OK

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


    1. Turn the ignition switch off.

    2. Connect the GTS to the DLC3.

    3. Start the engine.

    4. 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.: 0.00 V, max.: 5.00 V Brake pedal released: 0.20 to 0.40 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 GTS changes when the brake pedal is depressed.

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

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  3. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY)


    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 assembly/ ON or OFF

      ON: Brake pedal depressed

      OFF: Brake pedal released

      		 -

    2. Check that the stop light switch display observed on the GTS changes according to brake pedal operation.

      OK
      The GTS displays ON or OFF according to brake pedal operation.

    NG

    CHECK HARNESS AND CONNECTOR (STP TERMINAL) Click here

    OK

  4. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Drive the vehicle at a speed of 30 km/h (18 mph) or more and perform a braking test (decelerate the vehicle by depressing the brake pedal).

    6. Check if the same DTC is output Click here.

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

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A002MAPE01
      Text in Illustration
      *A for CVT
      *B except CVT
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      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 A78 (for CVT) or A79 (except CVT) skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage (for CVT)
      Tester Connection Condition Specified Condition
      A78-30 (STP) - Body ground Stop light switch assembly ON (Brake pedal depressed) 11 to 14 V*
      A78-30 (STP) - Body ground Stop light switch assembly OFF (Brake pedal released) Below 1.5 V
      Standard Voltage (except CVT)
      Tester Connection Condition Specified Condition
      A79-6 (STP) - Body ground Stop light switch assembly ON (Brake pedal depressed) 11 to 14 V*
      A79-6 (STP) - Body ground Stop light switch assembly OFF (Brake pedal released) Below 1.5 V

      Tech Tips

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


    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)