Most modern cars come with keyless entry controlled by a key fob that locks and unlocks your doors at the press of a button — they also engage the alarm, pop the trunk, and some even have remote start features. Since most keyless remotes are sold and programmed through a dealership, it can be an expensive item to replace...but only if it's really broken. Sometimes a non-functioning key FOB isn't actually broken.
If you're struggling to determine why your key fob isn't working, here are some quick and easy ways to pinpoint the problem.
Possible Problem One: Your Battery is Dead
The majority of the time, the battery is just dead in the key fob. This happens all of the time and will cause your key fob to stop working. What throws us off sometimes is that it doesn’t act as though it is draining and working slower or intermittently, at least the majority of the time. For the part, when the battery is dead, the key fob will just stop working altogether. A quick test, and a way back in your car in a pinch, is to pop the back off the fob and switch the batteries around (there’s usually two or more, if there’s only one, leave it alone), it may work one more time to get you in your vehicle. You can also take it to many local corner auto parts stores and have it tested at the battery kiosk in front of the store. If your battery is dead, all you have to do is replace the batteries and move on — that’s it, this is the easiest of the fix.
Possible Problem Two: The Circuit Board is Fried
If a battery tester shows your batteries are dead and you replace them without success, it’s likely that the circuit board is fried. This happens from coffee spills, impacts, and sometimes just overuse (not likely though, a fried circuit board usually needs help to get that way). If the battery replacement didn’t help, this is almost certainly the issue. You will then have to order a new circuit board from the dealership and have it reprogrammed for your car. With certain models, you can use your VIN to buy a reprogrammed circuit board, but that option varies. Also, most people just opt to buy a whole new fob assembly at this point.
Possible Problem Three: The Casing is Bad
A very worn casing can cause otherwise healthy internals to stop working. This is because the components are not mating together and the lack of contact keeps the signal from leaving the remote. The button pad may be too worn to make contact or the gasket sealing the fob shut may have become broken. When this happens, you will need to replace the casing of the remote and transfer over the circuit board and batteries into a new key fob. This will not require any further programming.
Possible Problem Four: The Programming is Wrong
Your key fob is programmed at the dealership to communicate specifically with your car, that’s why it can’t open any other vehicles. It’s just like a garage door operator, the motor/receiver and the remote work on an exclusive wave length. While it’s highly unlikely that the programming is off for no reason, it’s not entirely impossible either. If you have addressed all of the other previous issues and the key fob is still not working, reprogramming is the last common issue.A Note About Reprogramming: While most models need to be reprogrammed at the dealership, you can sometimes get away with reprogramming it yourself. Check out the post on reprogramming here — you might be lucky enough to handle it all on your own.