ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1281, C1421, C1422, C1423, C1424

DTC Code DTC Name
C1281 Master Cylinder Pressure Sensor Output Malfunction (Test Mode DTC)
C1421 Open or Short in Master Cylinder Pressure Sensor
C1422 Master Cylinder Pressure Sensor Zero Point High Malfunction
C1423 Master Cylinder Pressure Sensor Zero Point Low Malfunction
C1424 Master Cylinder Pressure Sensor Output Malfunction

DESCRIPTION

The master cylinder pressure sensor is connected to the skid control ECU in the brake actuator assembly.

A01CI4HE02
DTC No. DTC Detection Condition Trouble Area
C1421 PMC terminal voltage is less than 0.19 V or more than 4.57 V for 1.2 seconds or more continuously.

  • Stop light switch assembly

  • Harness or connector

  • Brake actuator assembly
C1422 With the stop light OFF, the vehicle is driven at a speed of more than 10 km/h, and the PMC terminal voltage is 0.86 V or more for 5 seconds or more continuously.
C1423 With the stop light OFF, the PMC terminal voltage is less than 0.3 volts for 5 seconds or more continuously.
C1424

When any of following conditions detected:


  • The vehicle speed is 7 km/h (4 mph) or more and the PMC terminal voltage does not change by at least 0.005 V during a period of 30 seconds or more.

  • At a vehicle speed of 10 km/h (6 mph) or more, noise occurs in the PMC terminal voltage 7 times or more within 5 seconds.

  • From a vehicle speed of 40 km/h (24 mph) or more, the stop light switch is turned on and remains on, and before the vehicle speed is reduced to 0 km/h (0 mph), the PMC terminal voltage decreases to 0.05 MPa or less 5 times or more.

  • At a vehicle speed of 7 km/h or more with a sensor output of 7 MPa or more, the deceleration calculated from the vehicle speed is in a low condition for 1 second or more continuously.

  • At a vehicle speed of 7 km/h or more with a sensor output of 3 MPa or less, the deceleration calculated from the vehicle speed is in a high condition for 1 second or more continuously.
C1281 Detected only during Test Mode. Brake actuator assembly

WIRING DIAGRAM

Refer to DTCs C1249 and C1425 Click here.

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. CHECK STOP LIGHT SWITCH 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
      Stop light switch function is normal.

    NG

    INSPECT STOP LIGHT CIRCUIT Click here

    OK

  2. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW, MASTER CYLINDER SENSOR)


    1. Warm up the engine.

    2. Turn the ignition switch off.

    3. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to ON.

    6. Turn the intelligent tester on.

    7. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    8. According to the display on the intelligent tester, read the Data List.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch / OFF or ON

      OFF: Brake pedal released

      ON: Brake pedal depressed

      		 -
      Master Cylinder Sensor Master cylinder pressure sensor reading / Min.: 0.00 V, Max.: 5.00 V When brake pedal is released: 0.30 to 0.70 V Reading increases when brake pedal is depressed.
      Standard
      Master cylinder pressure sensor reading is 0.86 V or less at the instant the stop light switch changes from off to on.

    NG

    CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    OK

  3. RECONFIRM DTC


    1. Clear the DTC Click here.

    2. Start the engine.

    3. Drive the vehicle at a speed of 40 km/h (25 mph) or more and perform braking test (decelerate the vehicle by depressing the brake pedal).

    4. Check if the same DTC is recorded Click here.

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

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  4. 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.

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

    NG

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY

    OK

  5. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Remove the stop light switch assembly Click here.

    2. A01CH1DE01
      Text in Illustration
      *a

      Component without harness connected

      (Stop Light Switch Assembly)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch pin free Below 1 Ω
      1 - 2 Switch pin pushed in 10 kΩ or higher

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (STP1 TERMINAL)


    1. Turn the ignition switch off.

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

    3. A01CIB3E12
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B9-23 (STP1) - Body ground

      Stop light switch on

      (Brake pedal depressed)

      		 20 to 28 V
      B9-23 (STP1) - Body ground

      Stop light switch off

      (Brake pedal released)

      		 Below 1.5 V

    4. Reconnect the skid control ECU (brake actuator assembly) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP1 CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here