Engine Control: SFI System
4GR-FSE ENGINE CONTROL: SFI SYSTEM: P0724: Brake Switch "B" Circuit High
P0724 - Brake Switch "B" Circuit High
DESCRIPTION
The purpose of this circuit is to prevent the engine from stalling, while driving with the lock-up torque converter clutch on, when brakes are suddenly applied.
When the brake pedal is depressed, the stop light 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 assembly remains on. When the stop light switch assembly remains on during "stop and go" driving, the ECM interprets this as a malfunction in the stop light switch assembly 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 (18.6 mph (30 km/h) or more) 5 times during 2 driving cycles, in order to detect a malfunction.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
CONFIRMATION DRIVING PATTERN
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG) and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) DTC Check / Clear.
- Turn the engine switch off.
- Turn the engine switch on (IG) and turn the Techstream on [A].
- Wait 5 seconds after clear the DTCs.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.
- Input the DTC: P0724.
- Check the DTC judgment result [B].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [C] through [E].
- Start the engine [C].
- Accelerate the vehicle to 18.6 mph (30 km/h) or more, depress the brake pedal and decelerate the vehicle to 1.86 mph (3 km/h) or less [D]. Repeat step [D] 5 times.
- Check the DTC judgment result [E].
- If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
- Read Pending DTCs.
HINT
If a pending DTC is output, the system is malfunctioning.
- If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.
HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
- Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. Reading the Data List information early in troubleshooting is one way to save diagnostic 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.
PROCEDURE
1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Data List / Stop Light Switch.
(e) Read the value displayed on the Techstream when the brake pedal is depressed and released.
OK:
NG -- INSPECT STOP LIGHT SWITCH ASSEMBLY
OK -- CHECK FOR INTERMITTENT PROBLEMS
2. INSPECT STOP LIGHT SWITCH ASSEMBLY P0504
NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY Removal
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)
(a) Disconnect the ECM connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
(c) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - STOP LIGHT SWITCH ASSEMBLY)
OK -- REPLACE ECM Removal