How to Fix a Key Fob That isn't Working
If your key fob isn't functioning There are a few simple steps that can fix it. The first step is to be sure that it's not the backup remote.
If your backup remote is unable to unlock and lock the doors of your vehicle, it is likely that the main remote isn't working. The most common causes of car remote key failure are issues with the circuitry or battery.
Battery
The battery in a key fob can get worn out over the course of time. It is easy to replace a battery. However it is crucial that you choose the right type. You can check your owner's guide or contact the manufacturer to determine the right kind. It is also important to inspect the battery compartment, since dead batteries can leak toxic chemicals that could damage the remote. If replacing the battery does not fix the problem there may be additional issues requiring professional attention. If the buttons are broken or stuck for instance, it may be necessary take the remote apart and rework each component. You could also try reprogramming the vehicle to recognize the new key fob.
Buttons
Key fobs can become dirty and worn out from frequent use. It is not unusual to have buttons stop functioning, or require a hard press to get them working. This can be very frustrating particularly when you're away from home and need to start your car. Fortunately, even worn-out or broken buttons can usually be fixed with just a bit of time and some of the materials you might already have in the house.
First, check that the batteries are charged correctly and that the indentation on the back of the button is filled. Then, carefully open the remote and examine the circuit board. Examine for signs of rust or other indications that the buttons are damaged or worn. For instance, conductive paint may be missing. Use the Q-tip, dipped in alcohol, gently clean any membrane contacts that are worn or where conductive paint is missing. Be careful not to rub too hard, as this can erode the conductive paint and stop the button from firing when pressed.
Check the battery connector terminals carefully for any loose solder connections. Soldering them back in place will allow the button to function again if this is the case. The same process can be used to restore functionality to any other loose connections in the fob.
If, for instance, any of the buttons made of rubber on the front of the key fob have stopped functioning or require a long press to function it is likely the graphite disks that are on the back of the button are deteriorating and need to be replaced. You can usually do this by rubbing a pencil over the disks. This will bring the button back to life.
If none of this is helpful, or if the button still doesn't respond to a firm press It could be that the circuit board itself has become damaged. It is possible to fix this by a quick clean, and re-soldering, but it is ideal to have a spare fob available in the event this method doesn't work for you.
Circuitry
Whether or not the keys fob buttons are functioning the circuit board that is inside the remote could be dirty. The issue can be solved by a thorough inspection. Broken cases and water are the most common causes of boards that are dirty. A damaged case allows water and other debris to pass through and short circuit the electronics. Water can also get through pins and vias, which are small connectors that are found on the board.
If you're able 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 may not work or even stick in their down position. Soldering the terminals and button's back in place is usually all it takes to restore a non-working key fob to working condition.
Non-Remote transponder chips
The non-remote chips that are sealed are more durable than remote fobs, but they are susceptible to breaking if a hole is drilled in them or when a door handle for a car or lawnmowers plows over them. nearby key repair shop of the time, non-remote transponder chip malfunctions could be attributed to blowing fuses.
If you're not comfortable opening the key fob, you may take the circuit board off and use a multimeter to verify that the diode is functioning properly. If you're not comfortable with this, you can visit your local Oreilly or hardware store and test their RF frequency tester. This will tell you whether the key fob sends an RF signal.
Programming
Key fobs aren't indestructible and are susceptible to being damaged through a variety of causes. They can break their connection with the receiver inside your vehicle due to shocks or a low battery, requiring changing the program. A professional auto locksmith or main dealer, can reprogram your keyfob and get it working again. If, in the unlikely event that resetting or repairing your key fob fails it could be the time to replace it entirely.