Shift Interlock: Description and Operation

The Brake Transaxle Shift Interlock (BTSI) System is designed to keep the driver from moving the gear selector out of "PARK" without the brake pedal being depressed. Battery voltage is applied to the BTSI Solenoid with the Ignition Switch in "RUN," "BULB TEST" or "START." This solenoid finds a ground path through the various stop lights with the brake pedal released. With the brake pedal released, the solenoid is energized and impedes the gear selector from being moved from the "PARK" position. When the brake pedal is depressed, battery voltage is applied to the ground side of the BTSI Solenoid. The solenoid is de-energized, allowing the gear selector to move freely from the "PARK" position.