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

Note

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 (STP circuit)

  • Wire harness or connector (GND1 circuit)

  • Stop light switch assembly

  • Skid Control ECU (brake Actuator Assembly)

Tire pressure warning light (w/ tire pressure warning system) is off.

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 and acceleration sensor 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.

      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.

    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

    for LHD:Click here

    for RHD:Click here

    OK

  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

    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. 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 > 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

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

  5. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

    1. C305133C09

      *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 A39 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

      A39-30 (STP) - Body ground

      Stop light switch ON (Brake pedal depressed)

      11 to 14 V*
      Tip:

      *: 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

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  6. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

    1. C305133C08

      *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

      A39-38 (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

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

  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

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    Click here

    OK

  8. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

    1. C305133C09

      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Reconnect the A20 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 A39 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

      A39-30 (STP) - Body ground

      Stop light switch ON (Brake pedal depressed)

      11 to 14 V*

      A39-30 (STP) - Body ground

      Stop light switch OFF (Brake pedal released)

      Below 1.5 V
      Tip:

      *: 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

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  9. RECONFIRM DTC

    1. Reconnect the A39 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 output.

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

        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

    A

    USE SIMULATION METHOD TO CHECK

    Click here

    B

    INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)

    Click here