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.

A005OJPE33
DTC No. Detection Item DTC Detection Condition Trouble Area
C1246 Master Cylinder Pressure Sensor Malfunction

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 circuit

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor (brake actuator assembly)
DTC Detection Conditions:
Vehicle Condition
Pattern 1 Pattern 2 Pattern 3
Diagnosis Condition - - - -
Malfunction Status The voltage of the sensor signal is out of range (below 0.129 V, above 3.29 V). ○ - -
An abnormality is detected in the skid control ECU internal sensor test. - ○ -
The sensor signal offset value is out of range. - - ○
Detection Time - - -
Number of Trips 1 trip 1 trip 1 trip

Tech Tips

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

A005PFEE01

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform system variant learning.

Click here

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
      Result
      Proceed to
      OK
      NG

    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


      Chassis > ABS/VSC/TRC/EPB > Data List
      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 When brake pedal released: 0.2 to 0.4 V Reading increases when brake pedal is depressed

      Chassis > ABS/VSC/TRC/EPB > Data List
      Tester Display
      Master Cylinder Sensor

    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.
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    C

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

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


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Select the Data List using the GTS.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Data List
      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

      		 -

      Chassis > ABS/VSC/TRC/EPB > Data List
      Tester Display
      Stop Light SW

    4. 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.
      Result
      Proceed to
      OK
      NG

    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


      Chassis > ABS/VSC/TRC/EPB > Clear DTCs

    3. Turn the ignition switch off.

    4. Start the engine.

    5. Drive the vehicle and depress the brake pedal several times to test the stop light circuit.

    6. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Trouble Codes
      Result
      Result Proceed to
      DTC C1246 is not output. A
      DTC C1246 is output. (for LHD) B
      DTC C1246 is output. (for RHD) C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.

      Click here


    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    C

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A005PMEC06
      *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 A42 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
      A42-44 (STP2) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V*
      A42-44 (STP2) - Body ground 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.

      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.

      Click here


    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)