SFI System
2AZ-FE ENGINE CONTROL: SFI SYSTEM: P0724: Brake Switch "B" Circuit High
P0724 - Brake Switch "B" Circuit High
DESCRIPTION
The stop light switch is part of a duplex system that transmits two signals: STP and ST1-. These two 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 assembly remains on. When the stop light switch assembly remains on during STOP and GO driving, the ECM interprets this as a fault in the stop light switch assembly. Then the ECM illuminates the MIL and stores the DTC.
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, 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.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
4. Turn the ignition switch off and wait for at least 30 seconds.
5. Turn the ignition switch to ON and turn the Techstream on [A].
6. Wait 5 seconds.
7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].
8. Read the pending DTCs.
HINT
* If a pending DTC is output, the system is malfunctioning.
* If a pending DTC is not output, perform the following procedure.
9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
10. Input the DTC: P0724.
11. Check the DTC judgment result.
HINT
* If the judgment result shows NORMAL, the system is normal.
* If the judgment result shows ABNORMAL, the system has a malfunction.
* If the judgment result shows INCOMPLETE or N/A, perform steps [C] through [E].
12. Start the engine [C].
13. Accelerate the vehicle to 30 km/h (18.65 mph) or more, depress the brake pedal and decelerate the vehicle to 3 km/h (1.86 mph) or less [D]. Repeat step [D] 5 times.
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
14. Check the DTC judgment result [E].
15. If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.
HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.
WIRING DIAGRAM
Refer to DTC P0504 P0504.
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
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 and ECT / Data List / Stop Light Switch.
(e) Read the values displayed on the Techstream.
Result:
NG -- INSPECT STOP LIGHT SWITCH
OK -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems
2. INSPECT STOP LIGHT SWITCH P0504
NG -- REPLACE STOP LIGHT SWITCH Components
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(d) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - ECM)
OK -- REPLACE ECM Components