Engine Control System

DTC P1520 Stop Light Switch Signal Malfunction

CIRCUIT 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 ECM. Then the ECM cancels operation of the lock-up clutch while braking is in progress.





DETECTING CONDITIONS





WIRING DIAGRAM

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INSPECTION PROCEDURE

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.