Engine Control System

2AZ-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 while driving in the lock-up condition when the brakes are suddenly applied.
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 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 be driven in GO (18.65 mph (30 km/h) or more) and STOP (less than 1.86 mph (3 km/h)) pattern 5 times in 2 driving cycles in order for the DTC to be output.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT:
- Using the Techstream's Data List allows switch, sensor, actuator and other item values to be read without removing any parts. Reading the Data List early in troubleshooting is one way to save time.
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.
NOTICE: In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

1. Warm up the engine.
2. Turn the ignition switch off.
3. Connect the Techstream to the DLC3.
4. Turn the ignition switch to the ON position.
5. Turn the Techstream on.
6. Enter the following menus: Powertrain / Engine and ECT / Data List.
7. Follow the instructions on the tester and read the Data List.





PROCEDURE

1. INSPECT STOP LIGHT SWITCH




(a) Remove the stop light switch.
(b) Measure the resistance between the terminals.
Standard resistance:





(c) Reinstall the stop light switch.
NG -- REPLACE STOP LIGHT SWITCH
OK -- Continue to next step.
2. CHECK WIRE HARNESS (ECM - BATTERY)




(a) Measure the voltage of the wire harness side connector.
(1) Disconnect the A24 ECM connector.
(2) Measure the voltage.
Standard voltage:






(3) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM