VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1426

DTC Code DTC Name
C1426 Stop Light Switch OFF Stuck Malfunction

DESCRIPTION

The skid control ECU receives stop light switch signals and uses them to determine whether or not the brakes are applied.

The skid control ECU has a detection circuit that it uses to detect a short in the stop light input line, or the ground line of the stop light circuit with the stop light switch on (brake pedal depressed).

If the skid control ECU detects a short in this circuit, it will store this DTC.

DTC No. DTC Detection Condition Trouble Area
C1426

Either of the following is detected:


  1. With the stop light switch off, the stop light switch is judged to be on based on the master cylinder pressure value for 3 seconds or more.

  2. With the stop light switch off, the master cylinder pressure is more than 8 MPa (81.6 kgf/cm2, 1160 psi) for 3 seconds or more.

  • STOP fuse

  • Stop light switch assembly

  • Stop light switch circuit

  • Ground circuit

  • Skid control ECU (Brake actuator assembly)

WIRING DIAGRAM

Refer to DTC C1249 Click here.

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the brake pedal height and stop light switch assembly installation Click here for LHD or Click here for RHD).

      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 the 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
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY Click here

    C

    ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY Click here

    A

  2. 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

    CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL) Click here

    OK

  3. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH ASSEMBLY)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Select the Data List using the intelligent tester Click here.

      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

      		 -

    4. Check that the stop light switch display observed on the intelligent tester changes according to brake pedal operation.

      OK
      The intelligent tester displays on or off according to brake pedal operation.

    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.

    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 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 before replacing parts Click here.


    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. A01EVRXE10
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Check that the STOP (7.5 A) fuse is normal.

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

    3. Disconnect the stop light switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A33-2 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  6. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. A01EWH3E01
      Text in Illustration
      *a

      Component without harness connected

      (Stop Light Switch Assembly)

      Measure the resistance according to 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

  7. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01EXFAE13
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Reconnect the stop light switch assembly connector.

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

    3. Disconnect the skid control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A49-30 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V*
      A49-30 (STP) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

      Tech Tips

      *: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  8. RECONFIRM DTC


    1. Reconnect the skid control ECU 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 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 before replacing parts Click here.


    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

    INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Click here

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01EXFAE13
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

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

    3. Disconnect the skid control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A49-30 (STP) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V*

      Tech Tips

      *: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  10. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A01EXFAE12
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A49-38 (GND1) - Body ground Always Below 1 Ω

      Tech Tips

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


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here