We get many questions where a car owner changes the key fob battery and the key still doesn't work. In some cases, a working car key stops working after changing the battery. To help you with this problem, we compiled a few tips to help you avoid such problems.
Handle the key fob circuit with care
When changing a key fob battery, handle the circuit inside the key fob with care. Also when opening the key case, be careful to not damage the key. If you car manual asks that you use a flat screwdriver, follow that recommendation. If you decide to use other objects to open up the case you may damage the housing.
Don't touch key fob circuit
Avoid touching the key fob circuit with your bare hands. Either handle the key fob circuit and electronic terminals with care or use gloves to change the remote battery.
Hold battery by the edges
If you hold the battery by pressing your fingers on the two flat surfaces you can shorten the battery life. Holding the battery this way can seriously deplete the battery capacity.
Note the battery positive (+) orientation
Before you remove the battery notice it's orientation. Is the positive (+) facing the back case or is it facing you. Note that only the (+) side of the battery is typically marked. The negative (-) side is not marked on most batteries.
Use correct battery type
If your remote uses CR2025 don't try to fit the wrong battery in the shell. Make sure to check with your owners manual the size of the battery and install the correct size. What's even worse is that you may end up installing a battery that has the wrong voltage and can end up ruining your expensive remote.
Synchronize or Program the key fob remote
Many car keys need to synchronized or programmed to the car after you replace the key fob battery. Some car models require that you insert the key into the ignition and start the car in order to learn the new key. Other may require that you carry a certain procedure to synchronize the keys to your car. If the Lock and Unlock feature do not work after you replace the key fob battery, look into your owners manual to see if the key needs to be programmed. In most cases you shouldn't need to see the dealer, this should be a procedure that you can carry at home.
Use a lithium battery
No need to use a NiCad battery. Instead, use a lithium when possible. They last at leat two to three times longer than the NiCad batteries and cost about the same.
Replace damaged key fob shell
If the buttons on your remote are worn out replace the key fob shell. Replacement shells typically cost less than $20 vs a new key for remote that can cost over $300 depending on the make and model.