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.
Description & Operation
The shift interlock system is mechanically operated using a cable connected between ignition switch and floor shifter or column shifter (depending on model). With ignition switch in LOCK or ACC positions, the gear selector is locked in Park. With ignition switch in OFF or RUN positions, the gear selector is unlocked and allows gear selector to move to any position. The shift interlock system also prevents the ignition switch from being returned to LOCK or ACC positions unless gear selector is returned to Park. The Brake Transmission Shift Interlock (BTSI) system (some models) consists of a cable and solenoid, and prevents transmission gear selector movement from Park without the ignition on and brake pedal depressed.
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.
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