VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1246, 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.

A01D5T5E33
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 pedal load sensing switch (brake pedal support assembly) (for 1AD-FTV)

  • Brake booster assembly

  • Master cylinder pressure sensor (brake actuator assembly)

WIRING DIAGRAM

A01D3WCE01

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 > 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
      Result Proceed to
      OK (for 1AD-FTV) A
      OK (except 1AD-FTV) B
      NG C

    B

    READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY) Click here

    C

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

  3. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY AND BRAKE PEDAL LOAD SENSING SWITCH)


    1. Select the Data List using the GTS.

      Click 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

      		 -
      Brake Pedal Load Sensing SW Brake pedal load sensing switch ON or OFF

      ON: Brake pedal depressed beyond a specified point

      OFF: Brake pedal not depressed beyond a specified point

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Stop Light SW
      Brake Pedal Load Sensing SW

    2. Check that the stop light switch display and brake pedal load sensing switch display observed on the GTS change according to brake pedal operation.

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

    3. Slowly depress the brake pedal, and check when the stop light switch and brake pedal load sensing switch turn on.

      OK
      First the stop light switch turns on, and then the brake pedal load sensing switch turns on.
      Result
      Result Proceed to
      OK A
      NG (The stop light switch does not turn on.) B
      NG (Turning on of the brake pedal load sensing switch is not confirmed.) C
      NG (The brake pedal load sensing switch turns on first.) D

    B

    CHECK HARNESS AND CONNECTOR (STP TERMINAL) Click here

    C

    INSPECT BRAKE PEDAL LOAD SENSING SWITCH Click here

    D

    CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    A

  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 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


      Chassis > ABS/VSC/TRC > Trouble Codes
      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. A01D4QPC05
      *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

      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
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

  6. INSPECT BRAKE PEDAL LOAD SENSING SWITCH

    A01D5WQC01
    *a

    Component without harness connected

    (Brake Pedal Load Sensing Switch (Brake Pedal Support Assembly))

    1. 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 A111 brake pedal load sensing switch connector.

      Note


      • Do not remove the brake pedal load sensing switch from the brake pedal support assembly.

      • When there is a malfunction in the brake pedal load sensing switch, replace the brake pedal support assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (FSW+) - 1 (FSW-)

      Switch OFF

      (Brake pedal depressed)

      		 950 to 1050 Ω
      2 (FSW+) - 1 (FSW-)

      Switch ON

      (Brake pedal released)

      		 203 to 223 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY for LHD: Click here
    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY for RHD: Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - BRAKE PEDAL LOAD SENSING SWITCH)


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

    2. Disconnect the A97 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A97-34 (FSW+) - A111-2 (FSW+) Always Below 1 Ω
      A97-34 (FSW+) or A111-2 (FSW+) - Body ground Always 10 kΩ or higher
      A111-1 (FSW-) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Turn the ignition switch off.

    2. Check the brake pedal height and stop light switch assembly installation.

      for LHD: Click here

      for RHD: Click here

      OK
      The brake pedal height and stop light switch assembly installation are normal.
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY for LHD: Click here
    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY for RHD: Click here

    NG

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY for LHD: Click here
    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY for RHD: Click here

  9. 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 > 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

  10. 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

      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

  11. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01D4QPC05
      *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

      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
      Proceed to
      OK
      NG

      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


    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)