P0724

1NZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0724: Brake Switch "B" Circuit High

DTC P0724 - Brake Switch "B" Circuit High

DESCRIPTION

The purpose of this circuit is to prevent the engine from stalling when brakes are suddenly applied while driving in lock-up condition.
When the brake pedal is depressed, this switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in progress.






MONITOR DESCRIPTION

This DTC indicates that the stop light switch remains ON. When the stop light switch remains ON during "stop and go" driving, the ECM interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC. The vehicle must stop (less than 1.86 mph (3 km/h)) and go (18.65 mph (30 km/h) or more) 5 times during 2 driving cycles, in order to detect a malfunction.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

The stop light switch remains ON during GO and STOP 5 times.

GO and STOP are defined as follows;





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: Read freeze frame data using a Techstream. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

PROCEDURE

1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)
(a) Connect a Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the tester ON.
(d) Select the following menu items: Powertrain / Engine and ECT / Data List / All Data / Stop Light Switch.
(e) Read the values displayed on the tester.
Standard:






NG -- CHECK STOP LIGHT SWITCH INSTALLATION
OK -- CHECK FOR INTERMITTENT PROBLEMS
2. CHECK STOP LIGHT SWITCH INSTALLATION
(a) Check the stop light switch installation Installation.
OK:
Stop light switch is installed correctly.
NG -- SECURELY REINSTALL STOP LIGHT SWITCH
OK -- Continue to next step.
3. INSPECT STOP LIGHT SWITCH ASSEMBLY P0504
NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)




(a) Disconnect the A21 ECM connector.
(b) Disconnect the A13 stop light switch connector.
(c) Check the resistance.
Standard resistance (Check for open):






Standard resistance (Check for short):





(d) Reconnect the ECM connector.
(e) Reconnect the stop light switch connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM