Key Fob Not Working? Check These Things Before You Pay Anyone
Put a new battery in the fob before you pay anybody anything. A plain coin cell costs a few dollars at any drugstore, and it fixes a huge share of "dead" fobs on the spot. Work through the checks below in order, cheapest first, and you'll either solve this for pocket change or know exactly what you're buying.
Try a new battery first
Most fobs take a CR2032, a flat silver coin cell about the size of a quarter. The exact type is stamped on the old battery or printed in your owner's manual. Pry the fob open at the seam with a coin or a small flathead screwdriver, and take a photo of the battery before you pull it so the new one goes in facing the same way.
Fobs rarely die without warning. If yours has only been working from two feet away, or you've had to click three times where one used to do, that's a battery fading, not a fob failing.
The hidden key will at least get you in
Locked out while you sort this out? Nearly every fob, including the ones for push-button-start cars, hides a mechanical key blade inside. Find the small release tab on the back or edge of the fob and slide the blade out. On keyless cars the keyhole itself is often hidden too, under a plastic cap on the driver's door handle. The alarm may go off when you open the door this way. Starting the car, or holding the fob against the start button on some models, usually silences it.
Re-pair the fob, then test your spare
Some cars drop a fob's pairing after a battery swap. The fix is a re-pairing procedure in the owner's manual, usually a timed sequence of ignition turns and button presses. It costs nothing and takes five minutes. Search the manual, or the automaker's site, for "remote programming."
Then grab your second fob. If the spare works, the problem fob is bad and you're shopping for one part. If neither fob works, stop shopping for fobs entirely, because the problem is the car. That usually means a failing receiver antenna, a door lock actuator, or the 12-volt battery under the hood. A weak 12-volt battery causes more phantom fob failures than most people would ever guess.
A wet fob needs contact cleaner, not rice
Rice does not fix electronics. It didn't save many phones and it won't save your fob. If the fob went through the wash or into the pool, open the case, pull the battery, and let the circuit board dry completely, overnight at least. Then spray the contacts with electronic contact cleaner, a few dollars a can at any auto parts store. If you see green or white corrosion and cleaning doesn't bring the fob back, it's done.
If you do need a new fob, buy it smart
Here's where the money is. A basic transponder key typically runs $75 to $250, and a smart or proximity fob typically runs $150 to $400 or more, depending on the car. We break down the whole pricing picture in our guide to car key replacement costs.
A warning about the $15 fobs on online marketplaces: plenty of them will not program to your car at all, and many locksmiths and dealers won't touch a customer-supplied fob, or they'll charge for the programming attempt whether it takes or not. A reputable automotive locksmith with the right part usually beats dealer pricing anyway, and comes to you. And if the dead fob was your only key, that's a bigger job. Expect around $200 to $600 for all-keys-lost service depending on the vehicle, and read our piece on losing all your car keys before you call anyone.
One last thing: change the battery in your spare fob today, while you're thinking about it. A spare that's been dead in a drawer for three years is just a plastic paperweight on the day you finally need it.
