Description & Operation: Introduction

The automatic transmission shift lock control is a safety device that prevents an inadvertent shift out of Park when the ignition switch is ON. 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 actuator (also known as "A/T shift lock control solenoid").
• The automatic transmission (A/T) shift lock control switch (stoplamp switch).
• The Park/Neutral Position (PNP) switch.

With the ignition switch in the ON position, battery voltage is supplied to the PNP switch. With the transmission in the Park position, the contacts in the PNP switch are closed. This allows current to flow through the switch to the stoplamp switch. The circuit continues through the normally-closed switch to the A/T shift lock control actuator. The A/T shift lock control actuator is permanently grounded. This energizes the A/T shift lock control actuator, mechanically locking the shift linkage in the Park position. When the driver presses the brake pedal the contacts in the stoplamp switch open, de-energizing the A/T shift lock control actuator. This allows the shift lever to move from the Park position.