How to Fix a Key Fob That isn't Working
If your key fob doesn't work and you're not sure why, you can fix it by following just a few steps. First, check to make sure it's not your backup remote.
If your backup remote cannot unlock and lock the doors of your car, it is likely that the main remote isn't functioning. The most frequent causes of key malfunctions for car remotes are issues with the circuitry or battery.
Battery
The battery in the key fob could get worn out over the course of time. It is quite simple to replace batteries, but it is important to ensure that you use the right type and you can consult your owner's manual, or contact the dealer for the manufacturer to find out the kind of battery you require. It's recommended to inspect the battery compartment thoroughly since dead batteries may leak caustic chemicals that can damage the remote. If changing the batteries doesn't solve the issue it could be that there are other issues that require attention from a professional. If buttons are broken or stuck for instance it might be necessary to disassemble the remote and rework each component. It is also possible to reprogramme the vehicle to recognize the new device.
car remote key repair
Through frequent use, key fobs may become worn and dirty. It is not uncommon for buttons to cease functioning, or require a long press to make them work. This can be a hassle especially when you're away from your home and you need to turn on your car. Fortunately, even worn out or broken buttons can usually be fixed with a little time and a few items you may already have around the home.
First, ensure that the batteries are charged correctly and that the indentation on the back of the button is filled. Then, open the remote with care and inspect the circuit board. Examine for indications of rust or other signs the buttons are worn or damaged. For example, conductive paint may be missing. Then, using the Q-tip, dipped in alcohol to gently clean any membrane contacts that are worn or have conductive paint missing. Avoid rubbing too hard, because this could damage the conductive paint and block the button from firing when it is it is pressed.
Check the battery connector terminals for loose solder connections. If this is the case, connecting them back can bring back function to the button. You can apply the same procedure to restore functionality to any other loose connection in the fob.
If any of the rubber buttons on the front of the keyfob isn't working or require being pressed extremely hard the graphite disks on the back of the button might have worn out and will require replacement. This can usually be done by rubbing a pencil over the disks. This should bring the button back to life.
If all of this doesn't help or if the button doesn't respond to a hard press It could be the case that the circuit board has gone bad. It is possible to fix the issue by cleaning and re-soldering the button however, you should have a spare in case it does not work.
Circuitry
The circuit board of your remote control could be dirty regardless of whether the buttons on the key fob are working or not. The issue can be solved through a thorough examination. Water and broken cases are the most frequent causes of boards that are dirty. A damaged case allows water and other debris to enter and short circuit the electronics. Water can also eat away at pins and small connectors on the board, which are known as via's.
If you're able to open your key fob and you don't mind making an mess, you can remove the buttons from their sockets and put in new ones. It's also worth looking at the battery terminal connections. If they are loose, the buttons could not function properly or become stuck in their down position. Soldering the terminals, and putting the button back in their place is generally all it takes to restore keys that are not in working condition.
Non-Remote Transponder Chips
Sealed non-remote transponder chips are much more durable than the remote fobs they are contained in, but they can be cracked by a hole that is drilled into them or over by a lawnmowers blade or car door handle. Fuse failures are usually the cause of non-remote chip failures.
If you're not confident opening the key fob, you can remove the circuitboard and utilize a multimeter to verify that the diode is operating properly. If you're not comfortable with this, visit your local Oreilly or hardware store and test their RF frequency tester. This will inform you whether the key fob is sending signals.
Programming
Key fobs take a lot of abuse and aren't indestructible. They may lose their connection with the receiver inside your vehicle due to shocks or low battery, requiring changing the program. A professional auto locksmith or dealer will be able to reprogram your key fob to get it working again. If resetting or replacing your key fob fails it is possible to replace it.