VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1426

DTC Code DTC Name
C1426 Stop Light Switch OFF Stuck Malfunction

DESCRIPTION

The skid control ECU (brake actuator assembly) inputs the stop light signal and brake operation condition. When the brake pedal is depressed and the stop light switch signal is not input, C1426 is output.

DTC No. DTC Detection Condition Trouble Area
C1426 When voltage at terminal +BS is 9.5 V or higher, vehicle is driven and brake pedal is operated, stop light switch signal is not input.

  • Wire harness or connector

  • STOP NO. 1 fuse

  • Stop light switch assembly

  • Skid control ECU (Brake actuator assembly)

WIRING DIAGRAM

Refer to DTCs C1425 Click here.

INSPECTION PROCEDURE

Note


  • When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information Click here.

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

PROCEDURE


  1. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION


    1. Check the brake pedal height installation Click here.

    2. Check the stop light switch assembly installation Click here.

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

      Tech Tips

      If the on/off status of the stop light switch assembly and pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and switch before inspecting the input signals and other related parts.


    NG

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  2. CHECK STOP LIGHT OPERATION


    1. Check that all 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

  3. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

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

    4. In accordance with the display on the GTS, read the Data List.

      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

      		 -

    5. 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.

    NG

    Click here

    OK

  4. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Turn the ignition 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 recorded 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 ACTUATOR ASSEMBLY Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  5. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Remove the stop light switch assembly Click here.

    2. Inspect the stop light switch assembly Click here.

      OK
      The stop light switch assembly is normal.

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  6. CHECK TERMINAL VOLTAGE (STP TERMINAL)


    1. A003DRZE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

    2. Reinstall the stop light switch assembly Click here.

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

    4. Disconnect the B92 skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B92-35 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      B92-35 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  7. RECONFIRM DTC


    1. Reconnect the B92 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine.

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

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

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

      Tech Tips

      If the lighting system is normal but the DTC is still output, replace the skid control ECU (brake actuator assembly) Click here.


    B

    INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Click here

    A

    USE SIMULATION METHOD TO CHECK Click here

  8. CHECK TERMINAL VOLTAGE (STP TERMINAL)


    1. Turn the ignition switch off.

    2. A003DRZE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

    3. Disconnect the B92 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
      B92-35 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      B92-35 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here