VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1246 and C1281

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

DESCRIPTION

The master cylinder pressure sensor is connected to the skid control ECU in the brake actuator assembly. DTC C1281 is cleared when the Lost Booster Pressure Judgment Check is performed correctly in Test Mode and the check indicates a pass, or when Test Mode ends. DTC C1281 is output only in Test Mode.

C106656E33

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)

C1281

Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC)

Detected only during Test Mode.

  • Stop light switch assembly

  • Brake booster assembly

  • Master cylinder pressure sensor (brake actuator assembly)

WIRING DIAGRAM

C334068E01

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 hereClick hereClick 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 hereClick here

      Chassis > ABS/VSC/TRC > 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 > 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

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click hereClick hereClick hereClick here

    OK

  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 hereClick here

      Chassis > ABS/VSC/TRC > 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 > 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 > 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 > Trouble Codes

      Result

      Result

      Proceed to

      DTC C1246 is not output.

      A

      DTC C1246 is output.

      B
      Tip:

      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 hereClick hereClick here

    A

    USE SIMULATION METHOD TO CHECK

    Click hereClick hereClick hereClick here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click hereClick hereClick hereClick here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

    1. C238832C05

      *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 A97 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

      A97-30 (STP) - Body ground

      Stop light switch ON (Brake pedal depressed)

      11 to 14 V*

      A97-30 (STP) - Body ground

      Stop light switch OFF (Brake pedal released)

      Below 1.5 V
      Tip:

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

      Result

      Proceed to

      OK

      NG
      Tip:

      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 hereClick hereClick here

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click hereClick hereClick hereClick here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)