SFI SYSTEM (w/ Secondary Air Injection System), Diagnostic DTC:P0724

DTC Code DTC Name
P0724 Brake Switch "B" Circuit High

DESCRIPTION

The stop light switch is part of a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly. This DTC indicates that the stop light switch remains on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC.

DTC No. DTC Detection Condition Trouble Area
P0724 Stop light switch remains on even when the vehicle is driven in a GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) pattern 5 times (2 trip detection logic).

  • Short in stop light switch signal circuit

  • Stop light switch assembly

  • ECM

MONITOR DESCRIPTION

This DTC indicates that the stop light switch remains on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC. The vehicle must GO (30 km/h (18.63 mph) or more) and STOP (less than 3 km/h (1.86 mph)) 5 times for 2 driving cycles in order for the DTC to be stored.

WIRING DIAGRAM

Refer to DTC P0504 Click here.

INSPECTION PROCEDURE

Tech Tips

Using the intelligent tester, the Data List item "Stop Light Switch" can be read.

Item

Measurement Item/

Range

 Normal Condition Diagnostic Note
Stop Light Switch

Stop light switch status/

ON or OFF

  • Brake pedal depressed: ON

  • Brake pedal released: OFF

 -

PROCEDURE


  1. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION


    1. Check the stop light switch assembly installation.

      OK
      Stop light switch assembly is installed correctly.

    NG

    SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY

    OK

  2. INSPECT STOP LIGHT SWITCH ASSEMBLY


    1. Inspect the stop light switch assembly Click here.


    NG

    REPLACE STOP LIGHT SWITCH ASSEMBLY

    OK

  3. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH)

    B007TWGE05
    Text in Illustration
    *a Depressed
    *b Released
    *c

    Front view of wire harness connector

    (to ECM)

    1. Disconnect the ECM connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B71-36 (STP) - Body ground Brake pedal is depressed 11 to 14 V
      Brake pedal is released Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here