If your key fob doesn't work then you can fix it by following some simple steps. The first step is to be sure that it's not your backup remote.
If the backup can lock and unlock your car doors, then there's a likely issue with the primary remote. The most frequent causes of car remote key failure are battery or circuitry issues.
Battery
It is not uncommon for the battery in a key fob for cars to wear out. It is fairly easy to change out batteries, but it is essential to make sure that you select the correct one and you can consult your owner's manual or contact the dealer of the manufacturer to find out the kind of battery you require. It's recommended to examine the battery compartment with care since dead batteries may release caustic chemicals that could cause damage to the remote. If replacing the battery does not fix the problem there may be additional issues that require professional attention. If the buttons are stuck or broken for instance it might be necessary to take the remote apart and rework each component. It is also possible to reprogramme the vehicle to recognize the new device.
Buttons
Key fobs can get dirty and worn out from repeated use. It is not uncommon for buttons to stop working, or to require a long push to make them work. This can be a hassle, especially when you are away from home and you need to turn on your car. Fortunately, even worn out or damaged buttons can be fixed with just a bit of time and a few items you may already have around the house.
First, check that the batteries are correctly placed and that the indentation at the back of the button has been filled. Then, carefully open up the remote and inspect the circuit board. Examine for evidence of rust, or other indications that the buttons have been damaged or worn out. For example there could be conductive paint missing. Use a Q-tip that has been dipped in rubbing alcohol to gently clean any membrane contact that has become worn out or where conductive paint is missing. Be careful not to rub too hard, because this could damage the conductive paint and stop the button firing when the button is pressed.
Also, be sure to check the battery connector terminals for an unattached solder connection. Soldering repair car key fob into place will restore the button's functionality in the event that this is the case. The same process can be used to restore functionality to any other loose connections inside the fob.
Finally, if any of the rubber buttons on the front of the key fob have stopped working or require a difficult press to function it is likely that the graphite disks that are on the back of the button are deteriorating and need to be replaced. This can be done by rubbing a pencil across the disks, which will bring the button back to its original state.
If all of this doesn't help or if the button still does not respond to a hard push It could be because the circuit board has become damaged. 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
If the key fob buttons are working the circuit board that is inside your remote might be dirty. A thorough examination is usually enough to fix this problem. The most common causes for dirty circuit boards are water and broken cases. A damaged case can allow water and other debris to enter and short circuit the electronic components. Water can also damage pins and small connectors on the board called via's.
If you're handy enough to open your key fob and don't mind making a mess, we can de-solder the buttons and put new ones in their place. It's also worth examining the battery terminal connections. They can get very dirty and if they're loose, the buttons might not work or even stay in their down position. Soldering terminals and buttons back to their proper positions is usually enough to return a malfunctioning fob back to working.
Non-Remote transponder chips
The sealed non-remote chips are more durable than remote fobs. However, they are susceptible to cracking when a hole is made in them or in the event that a door handle of a car or lawnmowers plows over them. Most of the time non-remote transponder chip malfunctions could be attributed to blowing fuses.
If you're able to open a sealed non-remote key fob and are willing to put up with the mess, you can take off the circuit board and test the fuse with an instrument to verify diode function. If you're not confident doing this, head to your local hardware store or the Oreilly's and they will usually have a RFID frequency tester that can tell you whether the key fob is sending signals.
Programming
Key fobs are not indestructible and are susceptible to being damaged by a lot of things. They may lose their connection with the receiver inside your vehicle due to shocks or low-battery, which requires the reprogramming. A professional auto locksmith or the main dealer, can reprogram your key fob and get it back up and running again. If resetting or repairing the keyfob is not working it may be necessary to replace it.
