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) inputs the stop light signal and brake operation condition.

When the brake pedal is depressed and the stop light switch signal is not input, C1426 is output.

DTC No. DTC Detection Condition Trouble Area
C1426

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)

WIRING DIAGRAM

Refer to DTCs C1422 and C1429 (See page and Click here).

CAUTION / NOTICE / HINT

Note


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

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

PROCEDURE


  1. CHECK BRAKE PEDAL HEIGHT AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the brake pedal height and stop light switch assembly installation (See page for LHD, 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 stop light switch assembly 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 HEIGHT OR STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here

    C

    ADJUST BRAKE PEDAL HEIGHT OR STOP LIGHT SWITCH ASSEMBLY INSTALLATION 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

    INSPECT STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  3. 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.

      ABS/VSC/TRC
      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

      		 -

    4. Check that the stop light switch assembly 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

    B

    CHECK HARNESS AND CONNECTOR (STP TERMINAL) Click here

    C

    INSPECT BRAKE PEDAL SUPPORT ASSEMBLY Click here

    D

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here

    A

  4. RECONFIRM DTC


    1. Turn the engine switch off.

    2. Clear the DTCs Click here.

    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.

      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.


    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  5. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Check the stop light switch assembly Click here.

      OK
      The stop light switch assembly is normal.

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (STPS TERMINAL)


    1. A01W2S8E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Integration Relay (Engine Room Junction Block Assembly))

      Disconnect the 1F No. 1 integration relay (engine room junction block assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1F-16 (STPS) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      1F-16 (STPS) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STPS CIRCUIT)

    OK

  7. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01W55QE02
      Text in Illustration
      *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 connectors.

    2. Disconnect the A40 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
      A40-35 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A40-35 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  8. RECONFIRM DTC


    1. Reconnect the 1F No. 1 integration relay (engine room junction block assembly) connector.

    2. Reconnect the A40 skid control ECU (brake actuator assembly) connector.

    3. Clear the DTCs Click here.

    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.

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

      Tech Tips


      • 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

  9. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. A01W55QE02
      Text in Illustration
      *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 connectors.

    3. Disconnect the A40 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
      A40-35 (STP) - Body ground Stop light switch assembly on (Brake pedal depressed) 8 to 14 V
      A40-35 (STP) - Body ground Stop light switch assembly off (Brake pedal released) Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)

    OK

  10. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    1. A01W4GYE02
      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
      A40-25 (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.


    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

  11. INSPECT BRAKE PEDAL SUPPORT ASSEMBLY


    1. A01W1V3E01
      Text in Illustration
      *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 connectors.

    3. Disconnect the A32 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
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here

    C

    REPLACE BRAKE PEDAL SUPPORT ASSEMBLY Click here

    A

  12. 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 connectors.

    2. Disconnect the A40 skid control ECU (brake actuator assembly) connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A40-23 (FSW+) - A32-2 (FSW+) Always Below 1 Ω
      A40-23 (FSW+) - Body ground Always 10 kΩ or higher
      A32-1 (FSW-) - 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.


    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR