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) 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 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 (brake actuator assembly) detects a short in this circuit, it will store this DTC.

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

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.


  • Wire harness or connector

  • Stop light switch assembly

  • Skid Control ECU (brake Actuator Assembly)

DTC Detection Conditions: C1426
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition - - -
Malfunction Status With the stop light switch off, the stop light switch is judged to be on based on the master cylinder pressure value. -

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

-
Detection Time 3 seconds or more 3 seconds or more
Number of Trips 1 trip 1 trip

Tech Tips

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

Refer to DTC C1249.

Click here

CAUTION / NOTICE / HINT

Note


  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning.

    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.

      for LHD: Click here

      for RHD: 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.

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

    B
    C
    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
      Result
      Result
      OK
      NG

    NG
    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/EPB > 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/EPB > 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
    OK
  4. RECONFIRM DTC


    1. Turn the ignition switch off.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC/EPB > 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 output.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Trouble Codes
      Result
      Result Proceed to
      DTC C1426 is not output. A
      DTC C1426 is output. (for LHD) B
      DTC C1426 is output. (for RHD) C

      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


    A
    B
    C
  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. B008K80C06
      *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 A42 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
      A42-44 (STP2) - 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.

      Result
      Proceed to
      OK
      NG

    NG
    OK
  6. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. B008K80C05
      *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
      A42-46 (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

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

    A
    B
    C
  7. 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
    OK
  8. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. B008K80C06
      *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 A42 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
      A42-44 (STP2) - Body ground Stop light switch ON (Brake pedal depressed) 11 to 14 V*
      A42-44 (STP2) - 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.

      Result
      Proceed to
      OK
      NG

    NG
    OK
  9. RECONFIRM DTC


    1. Reconnect the A42 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC/EPB > 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 output.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Trouble Codes
      Result
      Result Proceed to
      DTC C1426 is not output. A
      DTC C1426 is output. (for LHD) B
      DTC C1426 is output. (for RHD) C

      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


    A
    B
    C