Description & Operation

WARNING: Vehicle is equipped with Supplemental Inflatable Restraint (SIR) system. When servicing vehicle, use care to avoid accidental air bag deployment. SIR system-related components are located in various locations throughout interior and exterior of vehicle, depending on application. Do not use electrical test equipment on or near these circuits. If necessary, deactivate SIR system before servicing components. See AIR BAG DEACTIVATION PROCEDURES article in GENERAL INFORMATION.

The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of Park when the engine is running. The driver must press the brake pedal before moving the shift lever out of the Park position. The system consists of the following components:

The automatic transmission (A/T) shift lock control switch (part of stoplamp switch).
The automatic transmission (A/T) shift lock control solenoid, also referred to as brake transmission shift interlock solenoid (BTSI).

With the ignition switch in the ON position, battery voltage is supplied to the stoplamp switch. The circuit continues through the normally closed switch to the BTSI solenoid. The permanently grounded BTSI solenoid energizes and mechanically locks the shift lever in the Park position. When the driver presses the brake pedal, the contacts in the stoplamp switch open. This causes the BTSI solenoid to release, allowing the shift lever to move out of the Park position.