ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:C1426

DTC Code DTC Name
C1426 Stop Light Switch OFF Stuck Malfunction

DESCRIPTION

The skid control ECU (housed in the actuator assembly) inputs stop light switch signals and brake operation condition.

The skid control ECU has an open detection circuit, which stores this DTC when detecting an open in the stop light input line or the ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).

DTC Code DTC Detection Condition Trouble Area
C1426 When the brake pedal load sensing switch is on, the master cylinder pressure is 2 MPa or higher and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch is off for 2 seconds or more.

  • STOP fuse

  • Stop light switch

  • Stop light switch circuit

  • Brake actuator assembly (Skid control ECU)

  • Brake pedal load sensing switch (Brake with switch pedal sub-assembly)

WIRING DIAGRAM

Refer to DTC C1425 Click here.

INSPECTION PROCEDURE

Note


  • When replacing the brake actuator assembly, perform 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

    Click here

    OK

  2. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW/BRAKE PEDAL LOAD SENSING SW)


    1. Turn the ignition switch off

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the intelligent tester on.

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

      ABS/VSC/TRC
      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 specified point

      OFF: Brake pedal not depressed beyond specified point

      		 -

    6. Check that the stop light switch display and brake pedal load sensing switch display observed on the intelligent tester change according to the brake pedal operation.

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

    7. Slowly depress the brake pedal and check when the stop light switch and brake pedal load sensing switch are turned on.

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

    B

    Click here

    C

    ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION Click here

    A

  3. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs Click here.

    3. Start the engine.

    4. Depress the brake pedal several times to test the stop light circuit.

    5. Check if the same DTC is output Click here.

      Result
      Result Proceed to
      DTC C1426 is not output A
      DTC C1426 is output B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  4. CHECK TERMINAL VOLTAGE (STOP LIGHT SWITCH POWER SOURCE TERMINAL)


    1. Make sure that there is no looseness at the locking parts and connecting parts of the connectors.

    2. Disconnect the A5 stop light switch connector.

    3. A00O8VUE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A5-2 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  5. INSPECT STOP LIGHT SWITCH


    1. Remove the stop light switch Click here.

    2. A00OA0WE01
      Text in Illustration
      *a

      Component without harness connected

      (Stop Light Switch)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch pin not pushed in Below 1 Ω
      Switch pin pushed in 10 kΩ or higher

    NG

    REPLACE STOP LIGHT SWITCH Click here

    OK

  6. CHECK TERMINAL VOLTAGE (STP)


    1. Make sure that there is no looseness at the locking parts and connecting parts of the connectors.

    2. Disconnect the A6 skid control ECU connector.

    3. A00O37ME14
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A6-2 (STP) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  7. ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION


    1. Adjust the brake pedal height and stop light switch installation Click here.


    NEXT

  8. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Start the engine.

    3. Depress the brake pedal several times to test the stop light circuit.

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

      Result
      Result Proceed to
      DTC C1426 is not output A
      DTC C1426 is output B

    B

    REPLACE BRAKE WITH SWITCH PEDAL SUB-ASSEMBLY Click here

    A

    END