Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Shift Interlock System
Shift interlock system prevents shift lever from being moved from Park unless brake pedal is depressed and accelerator pedal is in idle position. In case of a malfunction, shift lever can be released by placing ignition key in key release slot near shift lever and pushing down. Voltage is provided to shift lock solenoid when ignition is on.
When brake pedal is depressed, battery voltage is applied to the PCM/TCM from brakelight switch. With accelerator pedal in idle position, voltage is applied to the PCM/TCM from the throttle position sensor. The PCM/TCM then supplies voltage to shift lock circuit in the interlock control unit. When A/T gear position switch is in "P" position, interlock control unit operates shift lock solenoid by controlling the ground circuit. When shift lock solenoid is energized, shift lever is released and can be moved.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.