VEHICLE STABILITY CONTROL SYSTEM, 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.

The skid control ECU incorporates a circuit to detect an open circuit. This DTC is output when an open circuit is detected in the stop light signal input line.

DTC No. DTC Detection Condition Trouble Area
C1425 When voltage at terminal +BS is 9.5 to 17.4 V, open circuit occurs between STP terminal circuits A and B for 0.3 seconds or more (except restart due to stop and start control*).

  • Wire harness or connector

  • Stop light switch assembly

  • Skid control ECU (brake actuator assembly)

*: w/ Stop and Start System

WIRING DIAGRAM

Refer to DTC C1422 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 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

  2. READ VALUE USING GTS (STOP LIGHT SWITCH ASSEMBLY)


    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

      		 -

    4. Check that the stop light switch assembly condition observed on the GTS changes according to brake pedal operation.

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

    NG

    CHECK HARNESS AND CONNECTOR (STP TERMINAL) Click here

    OK

  3. 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 C1425 is not output. A
      DTC C1425 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

  4. 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

  5. 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

  6. 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

  7. 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 C1425 is not output. A
      DTC C1425 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

  8. 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

      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 (STP CIRCUIT)