VEHICLE STABILITY CONTROL SYSTEM(for Vacuum Brake Booster), Diagnostic DTC:C1425

DTC Code DTC Name
C1425 Open in Stop Light Switch Circuit

DESCRIPTION

The skid control ECU (brake actuator assembly) detects the brake operating conditions through a signal transmitted by the stop light switch assembly.

DTC Code DTC Detection Condition Trouble Area
C1425 When the IG1 terminal voltage is between 9.5 and 17.4 V, an open STP terminal circuit continues for 3 seconds or more.

  • STP terminal circuit

  • Stop light switch assembly

  • Skid control ECU (Brake actuator assembly)

WIRING DIAGRAM

B001HM1E01

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (brake actuator assembly), perform calibration Click here.

PROCEDURE


  1. CHECK STOP LIGHT SWITCH 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

  2. READ VALUE USING GTS (STOP LIGHT SW)


    1. Turn the ignition switch off

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

      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

      		 -

    6. Check that the stop light switch display observed on the GTS changes according to the brake pedal operation.

      OK
      The GTS displays ON or OFF according to brake pedal operation.

    NG

    CHECK TERMINAL VOLTAGE (STP) Click here

    OK

  3. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Start the engine.

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

    4. Check if the same DTC is output Click here.

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

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

  4. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Inspect the stop light switch assembly Click here.

      OK
      The stop light switch assembly is normal.

    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY Click here

    OK

  5. CHECK TERMINAL VOLTAGE (STP)


    1. Make sure that there is no looseness at the locking parts and connecting parts of the connectors.

    2. Disconnect the A6 skid control ECU (brake actuator assembly) connector.

    3. B001CDXE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A6-2 (STP) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. RECONFIRM DTC


    1. Reconnect the A6 skid control ECU (brake actuator assembly) connector.

    2. Clear the DTC Click here.

    3. Start the engine.

    4. Drive the vehicle and depress the brake pedal several times to test the stop light circuit.

    5. Check if the same DTC is output Click here.

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

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here