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 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 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

  • Brake actuator assembly (Skid control ECU)

WIRING DIAGRAM

Refer to DTC C1425 Click here.

INSPECTION PROCEDURE

Note

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

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
    OK
  2. READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Select the Data List on 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

      -
      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

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

      OK
      The intelligent tester displays ON or OFF according to brake pedal operation.
    5. Slowly depress the brake pedal, and check that the stop light switch and brake pedal load sensing switch are turned on.

      OK
      First the stop light switch should be turned on, and then the brake pedal load sensing switch should be turned 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 is turned on first) C

    B
    C
    A
  3. RECONFIRM DTC


    1. Turn the engine 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 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
    A
  4. INSPECT STOP FUSE


    1. A019NA1E04
      Text in Illustration
      *1 Engine Room Relay Block
      *2 STOP Fuse

      Remove the STOP fuse from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      STOP (7.5 A) fuse Always Below 1 Ω

    NG
    OK
  5. INSPECT STOP LIGHT SWITCH


    1. Install the STOP fuse.

    2. Check the stop light switch Click here.

      OK
      The stop light switch is normal.

    NG
    OK
  6. INSPECT SKID CONTROL ECU (STP1 TERMINAL)


    1. A019NSDE28
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

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

    2. Disconnect the skid control ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A44-2 (STP1) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A44-2 (STP1) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

    NG
    OK
  7. RECONFIRM DTC


    1. Reconnect the skid control ECU connector.

    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 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
    A
  8. INSPECT SKID CONTROL ECU (STP1 TERMINAL)


    1. A019NSDE28
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      Turn the engine 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 Switch Condition Specified Condition
      A44-2 (STP1) - Body ground Stop light switch ON (Brake pedal depressed) 8 to 14 V
      A44-2 (STP1) - Body ground Stop light switch OFF (Brake pedal released) Below 1.5 V

      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.


    NG
    OK
  9. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION


    1. Turn the engine switch off.

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

      OK
      The brake pedal height and stop light switch installation are normal.
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG (for LHD) C
      NG (for RHD) D

      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
    C
    D
    A