2ZR-FE Engine Control

2ZR-FE 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 when brakes are suddenly applied while driving with the lock-up torque converter clutch on.

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

GO and STOP are defined as follows:

TYPICAL MALFUNCTION THRESHOLDS





WIRING DIAGRAM

Refer to DTC P0504 P0504.

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 Removal
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 Removal