Key fobs have made life much easier for drivers. Short for “finger operated button”, key fobs allow us to unlock all of the doors at once without having to fiddle with the keys.

Some cars are so sophisticated that they can be unlocked just by carrying the key fob with you as you approach the car. Unfortunately, the fobs use batteries which eventually run out of power. If your key fob battery went completely dead, you wouldn’t be able to start the car and could end up stranded somewhere. To prevent this from happening, there is a warning light on the dashboard that indicates when the battery should be replaced in the fob.

What the key fob battery low warning light means

When the key is in use, the computer monitors the output voltage of the fob’s battery. Once the voltage gets to a certain point, the warning light will illuminate on the dash to let you know to replace the batteries.

Most fobs can be pried open to access the battery so you may not have to take your car anywhere. Your owner’s manual may have information on what type of battery should be used and how to replace it. Otherwise you can find this information online. Make sure that you use the correct type of battery. A different battery will have a different voltage and the system may not register properly, even if the fob still works.

If you have multiple key fobs, it's a good idea to replace all of the batteries at the same time as they tend to run out at the same time. Keep in mind, some vehicles may require a reset procedure before the low battery key fob light will turn off.

Is it safe to drive with the key fob battery low warning light on?

This light doesn’t affect driveability so it is okay to use the car normally if the light is illuminated. If you let the battery get too low on voltage, you may not be able to start the car. Don’t ignore the light and change the batteries out to prevent this from happening to you. If your key fob doesn’t appear to be working normally, our certified technicians can help you diagnose any issues.

This article originally appeared on YourMechanic.com as What Does the Key Fob Battery Low Warning Light Mean? and was authored by Spencer Cates.


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