Signs your key fob battery is dying

The common warning signs

• You have to stand closer to the car before the lock or unlock button works.
• You press a button two or three times before the car reacts.
• The small light on the fob is dim, flickers, or no longer comes on.
• The dashboard shows a message such as "Key battery low" or "Key not detected".
• A push-button start car sometimes fails to find the key, then finds it on the next try.

Rule out the other causes first

Weak range can also come from radio interference near airports, cell towers or parking garages. Try the fob somewhere else before buying a battery.

If the spare fob works normally from the same spot, the problem is almost certainly the battery in the first fob.

How long a fob battery lasts

Most coin cells in key fobs last several years, but heavy use, cold weather and smart keys that talk to the car constantly drain them faster.

A fob stored right next to the car can drain sooner, because a smart key keeps answering the car's signal.

What to do next

1. Find your vehicle on FobCells to see the exact battery size and how to open the fob.
2. Buy the same size printed on the old cell. A thinner cell of the same diameter can fit loosely.
3. Keep the spare fob's battery fresh too, so you are never left without a working key.