Shift Interlock: Description and Operation

Interlock System

How the Circuit Works

Power Supply
Battery voltage is supplied at all times through fuse 13 (in the under-hood fuse/relay box) to the brake pedal position switch. When the brake pedal is pressed, battery voltage is supplied to the MICU in the driver's under-dash fuse relay box and to the PCM.

Battery voltage is supplied through fuse 32 (in the driver's under-dash fuse/relay box) to the shift lock solenoid and to the key interlock solenoid when the ignition switch is in the ON or START position.

Key Interlock
The key interlock solenoid receives battery voltage when the ignition switch is in the ON or START position. When the shift lever is moved out of PARK (P), the MICU provides a ground to the key interlock solenoid. The solenoid is then energized, which prevents the ignition switch from being turned to LOCK (0). When the shift lever is returned to PARK (P), the MICU removes ground from the key interlock solenoid allowing the ignition switch to be turned to LOCK (0).

Shift Position Interlock
The shift lock system reduces the risk of the starting the engine in gear. Starting the engine is possible only in the P and N positions. The shift lock solenoid is electronically controlled by the shift lock/reverse lock control system signals. The PCM grounds the shift lock solenoid to operate the solenoid.

With the shifter in the P position while pressing the brake pedal and the throttle fully closed, the shift lock solenoid is turned ON and the shift lock solenoid plunger is retracted. This releases the shift lock stop and allows the shift lever to be moved.

If the brake pedal is released or if the throttle is pressed, the shift lock solenoid will remain OFF and the shifter will be locked in the P position.

If the vehicle is accelerating above 6 mph (10 km/h) or deceleration above 5 mph (8 km/h) the shift lock solenoid will be turned OFF and the shifter cannot be moved into the R position.