VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1426

DTC Code DTC Name
C1426 Stop Light Switch OFF Stuck Malfunction

DESCRIPTION

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

The skid control ECU has an open detection circuit, which outputs 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 voltage at terminal IG1 is 9.5 V or higher, the brake pedal load sensing switch is ON, the master cylinder pressure is 2 MPa or more 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

  • Skid control ECU (Brake actuator assembly)

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

WIRING DIAGRAM

Refer to DTC C1425 Click here.

INSPECTION PROCEDURE

Note


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

  • When replacing the brake actuator assembly, perform zero point calibration and store system information Click here.

PROCEDURE


  1. READ VALUE USING GTS (STOP LIGHT SW/BRAKE PEDAL LOAD SENSING SW)


    1. Turn the engine switch off.

    2. Connect the GTS to the DLC3.

    3. Start the engine.

    4. Turn the GTS 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 the specified point

      OFF: Brake pedal not depressed beyond the specified point

      		 -

    6. 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.

    7. Slowly depress the brake pedal, and check that 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 (Turning on of the stop light switch is not confirmed) B
      NG (The brake pedal load sensing switch turns on first) C

    B

    Click here

    C

    ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION Click here

    A

  2. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Turn the engine switch off.

    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

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.


    B

    Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  3. CHECK HARNESS AND CONNECTOR (BATTERY - STOP LIGHT SWITCH)


    1. A01FDC4E06
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Turn the engine switch off.

    2. Disconnect the stop light switch connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A5-1 (B) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A5-3 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - SKID CONTROL ECU)


    1. Turn the engine switch off.

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

    3. Disconnect the A5 stop light switch connector.

    4. Disconnect the A13 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A5-2 (L) - A13-2 (STP) Always Below 1 Ω
      A5-2 (L) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01FH1RE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

      Turn the engine switch off.

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A13-2 (STP) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  6. ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION


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


    NEXT

  7. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Turn the engine switch off.

    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

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.


    B

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here

    A

    END