How to Fix a Key Fob That isn't Working
If your key fob doesn't work, you can fix it with just a few steps. The first step is to be sure that it's not the backup remote.
If the backup remote is able to lock and unlock your car door, then there's a likely issue with the main remote. The majority of car remote key malfunctions result from circuitry or battery problems.
Battery
The battery in the key fob may be worn out over time. It is fairly easy to change out a battery, although it is crucial to make sure that you choose the correct type that you can refer to your owner's manual, or contact the dealer for the manufacturer to find out what kind of battery you require. It is also crucial to inspect the battery compartment as batteries that are not working properly can release caustic chemicals that can harm the remote. If changing the batteries does not solve the problem it could be that there are other issues that require attention from a professional. If the buttons are stuck or broken for instance, it may be necessary disassemble the remote and rework each component. You can also try reprogramming the vehicle to recognize the new device.
Buttons
Due to frequent use, key fobs could get dirty and worn. This is not unusual however it can cause buttons to cease working or require a difficult press to get them to work. This can be a hassle especially when you're away from home and have to turn on your car. Even broken or damaged buttons are often fixable with a little effort and materials you already have at home.
First, ensure that the batteries are charged correctly and that the indentation on the back of the button is filled. Then, carefully open up the remote and look at the circuit board. Look for indications of rust or other signs the buttons have been worn or damaged. For example there could be conductive paint missing. Utilizing a Q-tip that has been dipped in alcohol to gently clean any membrane contacts that are damaged or where conductive paint is missing. Avoid rubbing too hard, because this could damage the conductive paint and block the button firing when the button is pressed.
Check the battery connector's terminals for loose solder connections. Soldering them back to their original position can restore the button's functionality If this is the situation. The same method can be used to restore function to any loose connections in the fob.
If any of the rubber buttons on the front of the keyfob isn't working or require being pressed very hard the graphite disks on the back of the button could have worn out and will require replacement. It is usually done by rubbing a pencil over the disks. This will bring the button back to life.
If all of this doesn't help or if the button does not respond to a hard press, then it may be the case that the circuit board is damaged. This can be fixed by a quick clean and refitting, but it's best to have an extra fob available in the event this method fails for you.
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If the keys fob buttons are functioning the circuit board in your remote might be dirty. This issue can be fixed through a thorough examination. Broken and damaged cases are the most frequent causes of dirty boards. A broken case allows water and other debris to get in and short out the electronic components. Water can also damage pins and connectors on the board called via's.
If you're handy enough to open your key fob and aren't afraid of a little mess, we can take off the buttons and solder new ones in their place. It's also worth looking at the battery terminal connections. They can get very dirty and if they're loose the buttons might not function or may even remain in their down position. Soldering the terminals and buttons back into place is typically all that's required to return keys that are not in working order.
Non-Remote transponder chips
Sealed non-remote transponder chips are more durable than the remote fobs that have them but they can still be damaged by a hole that is drilled into them or run over by a lawnmowers or car door handle. Most of the time, non-remote transponder chips fail, and this can be blamed on an exploded fuse.
If you're not confident opening the key fob, you can take the circuit board off and use a multimeter to determine if the diode is functioning correctly. If you don't feel comfortable with this, you can visit your local Oreilly or hardware store and test their RF frequency tester. This will inform you whether the key fob is sending a signal.
Programming
Key fobs endure many abuses and aren't completely indestructible. They may lose their connection to the receiver in your car due to shock or a low battery, which calls for the reprogramming. A professional auto locksmith, or a dealer in the main, can reprogram your keyfob to get it working again. If resetting or replacing your key fob fails, you may need to replace it.