How to Leave a Car Running With Doors Locked – 2 Methods

To maintain your preferred temperature during extremely hot or cold weather, you may occasionally be obliged to leave your car running. Due to security concerns, you will need to lock your car.

For this situation, you’ll need to utilize the spare key you always keep on hand, start your car engine as usual, and then leave it running. Use your spare key to manually lock up your doors while the other one is still inside. This is simple to accomplish in vehicles that still use manual keys.

This article will explore more on how to leave the car running with doors locked.

How to Leave the Car Running With Doors Locked?

how to leave a car running with doors locked

Leaving your car running sometimes is necessary, especially during extremely hot or cold seasons and you have to run errands. Turning your car engine off severally will affect your temperature. You can use your spare key to lock your car as you leave the other inside.

Possible ways you can use to leave your car running with locked doors:

Use an input system without a key that lets you start the car with a remote control. However with some vehicles with keyless entry, you can use the pushbutton system to start your car, this does not require a key.

You Can Also Basically:

  • Turn on your car engine
  • Then exit without turning off the engine as you leave the key in.
  • Always ensure to carry your extra key with you at all times
  • Finally, using the extra key, manually lock the car doors.

Another Possible Way Is To:

  • Turn on your car engine as usual
  • Open the window as you exit the car.
  • Lock the door through the window by pressing the lock button.
  • Then press the automatic window close button to close it.
  • Finally, remove your hand before the window is fully closed and ensure that you have the extra key with you to use to unlock the car.

Finally, another alternative is to use a valet key which only unlocks the driver’s door. You can always locate your valet key in the glove compartment and ensure to always have it with you at all times.

How to Keep a Car Running Without the Key?

Ideally, this is only doable if your car uses keyless ignition because you will only need the FOB to turn it on or off and not to keep it running. You can leave it running as you go with the key FOB.

This may not be recommended in most states due to the excess emission of carbon monoxide that is harmful to human life and might even cause death especially left in the house garage.

Is It Possible to Lock Keys in a Car With Keyless Entry?

Keyless input cars may be locked with the key inside, you will need FOB to enable and disable your car. In your car is a button that locks your car. You can turn off your car and leave the key inside it will automatically lock once you are away from it.

Also, you can use the key found in the FOB to manually lock your car from the outside, even if the doors are keyless. It just takes starting the car, leaving it, and locking it with the manual key from the outside.

What to Do if You Lock Your Keys in the Car While It’s Running?

Sometimes, you might forget your extra key in the car and you’ve already locked it. You will have to call a locksmith to help you open the door if your car doesn’t have keyless entry codes. For cars with keyless entry, your car won’t lock if the FOB is still in the car while it’s running.

Is It Illegal to Leave Your Engine Running?

Certainly, yes it is illegal to leave your car running. In some states, it is prohibited to leave idling, as it is polluting the environment and produces carbon monoxide gas which is harmful to humans. If found, you might end up paying a hefty fine to the state.


For shorter periods it is okay however, longer times leaving your engine running may cause more motor oil to be circulated and burned up. This will eventually cost you due to frequent oil changes. it is also not good for the environment due to air pollution.

Ideally, Leaving Your Car Running All Day Will Not Cause Any Damage, as long as the Engine’s Cooling System Is Functioning Ordinarily. Most Modern Cars Can Run for Days, It Will Only Stop When It’s Out of Gas, Without Causing Any Harm to Themselves.

The normal time recommended by experts is thirty seconds to one minute. Conversely, the reason behind it is to conserve fuel and reduce the amount of air pollution to the environment. Nevertheless, a car’s engine can run indefinitely outdoors without any safety concerns.

Depending on your car model, some modern cars lock themselves, if left unlocked and empty for a lengthy period.  This feature is typically presented in cars equipped with sensors that detect the presence of people in the car.


Generally, leaving your car running is not recommended in some states due to air pollution to the environment and might also lead you to incur some costs, like oil changes frequently. You can leave your car running to maintain your temperature during extremely hot or cold seasons, also, ensure to keep an extra key with you daily.