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.
Automatic Transmission Shift Interlock System: Description
Transmission/Transaxle is equipped with a electronically controlled shift lock and mechanically controlled key lock system. Shift lock system prevents shift lever from being moved from Park unless brake pedal is depressed and key installed in ignition switch. Key lock system prevents ignition key from being moved from ACC to LOCK position on ignition switch unless shift lever is in Park.
System consists of brakelight switch, key interlock cable (all models except Q45), key lock solenoid (Q45), shift lock control switch, shift lock solenoid, park position switch and shift lock control unit (J30, Q45 and 1997 Sentra).
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.