Shift Interlock: Description and Operation

Interlock System A/T

How the Circuit Works

Key Interlock

Inserting the key into the ignition switch provides a ground signal to the MICU. If the shift lever is in PARK, the MICU provides voltage to the key interlock solenoid, energizing the solenoid and allowing the key to be turned to the LOCK (0) position.

Shift Position Interlock

Fuse 12 (in the under-hood fuse/relay box) supplies battery voltage at all times to the brake pedal position switch. With the ignition in ON (II) or START (II), fuse 10 (in the under-dash fuse/relay box) provides battery voltage to the shift lock solenoid. When the brake pedal is pressed, battery voltage is applied through the LT GRN wire to the PCM. If, at the same time, you do not press the accelerator pedal, the PCM applies ground through the RED wire to the shift lock solenoid. The solenoid energizes, allowing the shift lever to be moved from the PARK position.

If the vehicle is in motion (in NEUTRAL, DRIVE, 2 or 1), the MICU and PCM detect the motion, and remove ground from the shift lock solenoid.No longer energized, the shift lock solenoid will not allow the shift lever to be moved into REVERSE or PARK.