VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1422, C1281

DTC Code DTC Name
C1422 Master Cylinder Pressure Sensor Zero Point High 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 will be deleted when the master cylinder pressure sensor sends a master cylinder pressure signal or when Test Mode ends. DTC C1281 is output only in Test Mode.

A01G79KE34
DTC No. DTC Detection Condition Trouble Area
C1422 When the stop light switch is off, the PMC terminal voltage is more than 0.86 V for 5 seconds or more.

  • Stop light switch circuit

  • Master cylinder pressure sensor circuit

  • Master cylinder pressure sensor (Brake actuator assembly)
C1281 Detected only during Test Mode.

  • Stop light switch assembly

  • Brake pedal load sensing switch (Brake pedal support assembly)

  • Brake booster assembly

  • Master cylinder pressure sensor (Brake actuator assembly)

WIRING DIAGRAM

Refer to DTCs C1425 and C1429 Click here and Click here.

INSPECTION PROCEDURE

Note


  • When replacing the skid control ECU (brake actuator assembly), perform 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. 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: 0.30 to 0.90 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 ASSEMBLY AND BRAKE PEDAL LOAD SENSING 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 assembly / 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

      		 -

    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 should turn on, and then the brake pedal load sensing switch should turn 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 SUPPORT ASSEMBLY Click here

    D

    CHECK BRAKE PEDAL HEIGHT AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    A

  4. RECONFIRM DTC


    1. Turn the engine switch off.

    2. Clear the DTCs Click here.

    3. Turn the engine switch off.

    4. Start the engine.

    5. At a speed of 30 km/h (18 mph) or more, drive the vehicle 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 C1422 is not output. A
      DTC C1422 is output. B

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01G4YLE17
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the engine switch off.

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

    3. Disconnect the A40 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
      A40-2 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V
      A40-2 (STP) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  6. INSPECT BRAKE PEDAL SUPPORT ASSEMBLY


    1. A01G5EWE01
      Text in Illustration
      *a

      Component without harness connected

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

      Turn the engine switch off.

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

    3. Disconnect the A32 brake pedal load sensing switch (brake pedal support assembly) 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

    NG

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - BRAKE PEDAL SUPPORT ASSEMBLY)


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

    2. Disconnect the A40 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
      A40-27 (FSW+) - A32-2 (FSW+) Always Below 1 Ω
      A40-27 (FSW+) - Body ground Always 10 kΩ or higher
      A32-1 (FSW-) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  8. CHECK BRAKE PEDAL HEIGHT AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Turn the engine switch off.

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

      OK
      The brake pedal height and stop light switch assembly installation are normal.

    NG

    ADJUST BRAKE PEDAL HEIGHT OR STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    OK

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here