Yes, you can often lock your car while the engine is running, but it is generally not recommended due to significant risks of theft, safety hazards, and potential legal issues. The ability to do this depends on your specific vehicle's features. Many modern cars with keyless ignition systems (where the key fob is a separate device) will prevent you from locking the doors with the fob outside the vehicle while the engine is on, as a built-in anti-lockout feature. However, if you use a physical key to manually lock the door from the outside after exiting, you might succeed, but this is where the dangers begin.
The primary risk is vehicle theft. A running car is an easy target for thieves. Beyond the loss of the car itself, you could be held liable if the thief causes an accident. There are also serious safety concerns. A running car in an enclosed space, like a garage, can lead to a fatal buildup of carbon monoxide gas. Furthermore, many local municipalities have laws against idling vehicles, especially unattended ones, which could result in a fine.
If you need to briefly leave the car running—for instance, to quickly run into a store on a very hot or cold day to keep the climate control active—you must check your vehicle's capabilities. The safest method is to use a secondary key. Take your primary key fob with you and use a physical spare key to manually lock the door. Never leave a vehicle with a keyless system running and unattended if you cannot physically lock it, as this is an open invitation for theft.
| Vehicle Feature | Can You Lock It While Running? | Primary Risk | Recommended Action |
|---|
| Traditional Physical Key | Often Yes (via manual lock) | High risk of theft | Avoid doing so; use a spare key if absolutely necessary. |
| Keyless Ignition (Push-Button Start) | Usually No (anti-lockout feature) | Potential for accidental lockout | Rely on the vehicle's built-in safety feature. |
| Remote Start System | Yes (designed for this) | Minimal if used correctly | The safest way to warm up/cool down a car securely. |
| Valet Key | Sometimes | Theft of items in trunk/glovebox | Understand the key's limited access permissions. |
