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.

A004KOSE07
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 fuse

  • Stop light switch circuit

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor (Brake actuator assembly)

WIRING DIAGRAM

Refer to DTCs C1249 Click here.

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform VSC sensor neutral memorization 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. Connect the GTS to the DLC3.

    2. Start the engine.

    3. Select the Data List using 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

    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, the 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 using 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 switch display observed on the GTS change according to brake pedal operation.

      OK
      The GTS displays on or off according to brake pedal operation.

    NG

    CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL) Click here

    OK

  4. RECONFIRM DTC


    1. Clear the DTCs Click here.

    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 Click here.

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

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. A004H7GE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Noise Filter)

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

    2. Disconnect the noise filter connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A13-3 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  6. INSPECT NOISE FILTER


    1. Remove the noise filter Click here.

    2. Inspect the noise filter Click here.


    NG

    REPLACE NOISE FILTER Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (NOISE FILTER - STOP LIGHT SWITCH ASSEMBLY)


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

    2. Disconnect the stop light switch assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-2 - A22-1 Always Below 1 Ω
      A13-1 - A22-2 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Remove the stop light switch assembly Click here.

    2. Inspect the stop light switch assembly Click here.


    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A004HOJE01
      Text in Illustration
      *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 skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A5-30 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V*
      Stop light switch 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)