Engine Control - SFI System

2GR-FE ENGINE CONTROL: 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 lock-up condition, when 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 "stop and go" driving, the ECM interprets this as a malfunction 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





TYPICAL MALFUNCTION THRESHOLDS





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON and turn the Techstream on [A].
3. Clear the DTCs (even if no DTCs are stored, perform the Clear DTC procedure) DTC Check / Clear.
4. Wait 5 seconds after clear the DTCs.
5. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
6. Input the DTC: P0724.
7. 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].

8. Start the engine [C].
9. Accelerate the vehicle to 19 mph (30 km/h) or more, depress the brake pedal and decelerate the vehicle to 1.8 mph (3 km/h) or less [D]. Repeat step [D] 5 times.
10. Check the DTC judgment result [E].
11. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
12. Read Pending DTCs.
HINT: If a pending DTC is output, the system is malfunctioning.

13. 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(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




(a) Disconnect the stop light switch assembly connector.
(b) Remove the stop light switch assembly.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





(d) Reinstall the stop light switch assembly.
(e) Reconnect the stop light switch assembly connector.

NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
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