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.

Detection Item

DTC Detection Condition

Trouble Area

C1426

Stop Light Switch OFF Stuck Malfunction

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 fuse

  • Stop light switch assembly

  • Skid Control ECU (Brake actuator assembly)

WIRING DIAGRAM

Refer to DTC C1380.

Click here

CAUTION / NOTICE / HINT

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 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.

    Tip:

    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.

    Result

    Proceed to

    OK

    NG
    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

    Result

    Proceed to

    OK

    NG
    NG

    INSPECT STOP LIGHT SWITCH ASSEMBLYClick 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. Select the Data List using the GTS.

      Click here

      Chassis > ABS/VSC/TRC > Data List

      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

      -

      Chassis > ABS/VSC/TRC > Data List

      Tester Display

      Stop Light SW

    4. 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.

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (STP TERMINAL)Click here

    OK

  4. RECONFIRM DTC

    1. Turn the ignition switch off.

    2. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    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

      Chassis > ABS/VSC/TRC > Trouble Codes

      Result

      Result

      Proceed to

      DTC C1426 is not output.

      A

      DTC C1426 is output.

      B
      Tip:

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

      Click here

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

  5. INSPECT STOP LIGHT SWITCH ASSEMBLY

    1. Check the stop light switch assembly.

      Click here

      OK

      The stop light switch assembly is normal.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

    1. Turn the ignition switch off.

    2. C342353C29

      *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 A80 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

      A80-35 (STP) - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  7. RECONFIRM DTC

    1. Reconnect the A80 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    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

      Chassis > ABS/VSC/TRC > Trouble Codes

      Result

      Result

      Proceed to

      DTC C1426 is not output.

      A

      DTC C1426 is output.

      B
    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    INSPECT LIGHTING SYSTEM

    Click here

  8. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

    1. Turn the ignition switch off.

    2. C342353C29

      *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 A80 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

      A80-35 (STP) - Body ground

      Brake pedal depressed

      8 to 14 V

      Brake pedal released

      Below 1.5 V

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)