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VEHICLE STABILITY CONTROL SYSTEM, Diagnostic DTC:C1426

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DTC Code DTC Name
C1426 Stop Light Switch OFF Stuck Malfunction
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DESCRIPTION

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

The skid control ECU (brake actuator assembly) has a detection circuit that it uses to detect an open in the stop light input line.

If the skid control ECU (brake actuator assembly) detects an open in this circuit, it will store this DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area
C1426 Stop Light Switch OFF Stuck Malfunction

When the brake pedal load sensing switch is on, the master cylinder pressure is 2 MPa (20.4 kgf/cm2, 290 psi) or more and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch assembly is off for 2 seconds or more.

  • Wire harness or connector

  • Stop light switch assembly

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

  • Skid control ECU (brake actuator assembly)
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WIRING DIAGRAM

Refer to DTC C1425.

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Refer to DTC C1429.

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CAUTION / NOTICE / HINT

Note:

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

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

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PROCEDURE


  1. Click here

    CHECK BRAKE PEDAL HEIGHT AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the brake pedal height and stop light switch assembly installation.

      for LHD:Click here

      for RHD: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 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 stop light switch assembly before inspecting the input signals and other related parts.

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      ADJUST BRAKE PEDAL HEIGHT OR STOP LIGHT SWITCH ASSEMBLY INSTALLATION for LHD:Click here

      ADJUST BRAKE PEDAL HEIGHT OR STOP LIGHT SWITCH ASSEMBLY INSTALLATION for RHD:Click here

  2. Click here

    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
      Result
      Proceed to
      OK
      NG

  3. Click here

    READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY AND BRAKE PEDAL LOAD SENSING SWITCH)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Select the Data List using the GTS.

      Click here


      1. Chassis > ABS/VSC/TRC > Data List
        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

        		 -
        Brake Pedal Load Sensing SW Brake pedal load sensing switch ON or OFF

        ON: Brake pedal depressed beyond a specified point

        OFF: Brake pedal not depressed beyond a specified point

        		 -




      1. Chassis > ABS/VSC/TRC > Data List
        Tester Display
        Stop Light SW
        Brake Pedal Load Sensing SW





    4. 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.

    5. Slowly depress the brake pedal, and check when the stop light switch assembly and brake pedal load sensing switch turn on.

      OK
      First the stop light switch assembly should turn on, and then the brake pedal load sensing switch should turn on.
      Result
      Result Proceed to
      OK A
      NG (The stop light switch assembly does not turn on.) B
      NG (Turning on of the brake pedal load sensing switch is not confirmed.) C
      NG (The brake pedal load sensing switch turns on first.) D

  4. Click here

    RECONFIRM DTC


    1. Turn the engine switch off.

    2. Clear the DTCs.

      Click here


      1. Chassis > ABS/VSC/TRC > Clear DTCs


    3. Turn the engine 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


      1. 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 before replacing parts.

      Click here


  5. Click here

    CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. B0066KWC35
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      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 A15 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
      A15-2 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A15-2 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

  6. Click here

    CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B0066KWC36
      *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
      A15-1 (GND1) - Body ground Always Below 1 Ω
      Tip:

      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

      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE BRAKE ACTUATOR ASSEMBLY for LHD:Click here

      REPLACE BRAKE ACTUATOR ASSEMBLY for RHD:Click here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

  7. Click here

    INSPECT BRAKE PEDAL SUPPORT ASSEMBLY


    1. B0065SNC01
      *a

      Component without harness connected

      (Brake Pedal Load Sensing Switch (Brake Pedal Support Assembly))

      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 A51 brake pedal load sensing switch (brake pedal support assembly) connector.

      Note:

      • Do not remove the brake pedal load sensing switch from the brake pedal support assembly.

      • When there is a malfunction in the brake pedal load sensing switch, replace the brake pedal support assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (FSW+) - 1 (FSW-) Brake pedal load sensing switch off (Brake pedal depressed) 950 to 1050 Ω
      2 (FSW+) - 1 (FSW-) Brake pedal load sensing switch on (Brake pedal released) 203 to 223 Ω
      Result
      Proceed to
      OK
      NG

  8. Click here

    CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - BRAKE PEDAL SUPPORT ASSEMBLY)


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

    2. Disconnect the A15 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-27 (FSW+) - A51-2 (FSW+) Always Below 1 Ω
      A15-27 (FSW+) or A51-2 (FSW+) - Body ground Always 10 kΩ or higher
      A51-1 (FSW-) - Body ground Always Below 1 Ω
      Tip:

      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

      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE BRAKE ACTUATOR ASSEMBLY for LHD:Click here

      REPLACE BRAKE ACTUATOR ASSEMBLY for RHD:Click here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. Click here

    INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Inspect the stop light switch assembly.

      Click here

      OK
      The stop light switch assembly is normal.
      Result
      Proceed to
      OK
      NG

  10. Click here

    CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. B0066KWC35
      *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.

    2. Disconnect the A15 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
      A15-2 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A15-2 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

  11. Click here

    CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. B0066UHC07
      *a

      Front view of wire harness connector

      (to Semiconductor PWR Integration ECU)

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

    2. Disconnect the 2D semiconductor PWR integration ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2D-10 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      2D-10 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

  12. Click here

    RECONFIRM DTC


    1. Reconnect the A15 skid control ECU (brake actuator assembly) connector.

    2. Reconnect the 2D semiconductor PWR integration ECU connector.

    3. Clear the DTCs.

      Click here


      1. Chassis > ABS/VSC/TRC > Clear DTCs


    4. Turn the engine switch off.

    5. Start the engine.

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

    7. Check if the same DTC is output.

      Click here


      1. Chassis > ABS/VSC/TRC > Trouble Codes


      Result
      Result Proceed to
      DTC C1426 is not output. A
      DTC C1426 is output. B
      Tip:

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

        for LHD:Click here

        for RHD:Click here

      • 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