How to Fix a Key Fob That isn't Working
If your key fob does not work and you're not sure why, you can fix it with a few simple steps. First, make sure that it's not the backup remote.
If your backup remote cannot lock and unlock the doors of your car, then it is most likely that the primary remote isn't working. The most common causes for car remote key failure are circuitry or battery issues.
Battery
It is not uncommon to find a battery on a key fob for cars to get worn out. It is fairly easy to replace a battery, although it is important to ensure you select the correct one; you can look in your owner's manual or contact the manufacturer's dealer to find out what kind of battery you require. It is recommended to inspect the battery compartment thoroughly, as dead batteries sometimes leak caustic chemicals that can cause damage to the remote. If replacing the batteries doesn't solve the issue it could be because there are other issues that require professional attention. For instance, if the buttons seem stuck or broken, it may be necessary to take the remote apart and rework its components. You could also try reprogramming the vehicle to recognize the new key fob.
Buttons
Key fobs can become dirty and worn-out from repeated use. It is not uncommon to have buttons stop functioning, or require a long press to make them work. This can be frustrating especially when you're away from your home and need to switch on your car. Even broken or damaged buttons are often fixable with a little effort and the tools you already have at home.
First, verify that the batteries have been correctly installed and that the indentation on the back of the button has been filled. Then, open the remote with care and inspect the circuit board. Examine 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 dipped in rubbing alcohol, gently clean any membrane contacts that have worn or have conductive paint missing. Don't rub too hard in order to damage the conductive paint and prevent the button from firing when it is 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. You can follow the same process to restore functionality to any other loose connection inside the fob.
If any of the rubber buttons located at the front of the keyfob aren't functioning or require to be press very hard the graphite disks on the back of the button may 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 still doesn't respond to a firm press, then it may be because the circuit board has gone bad. It is possible to fix this issue by cleaning and re-soldering the fob but you should also have an extra in case it does not work.
Circuitry
If the keys fob buttons are functioning, the circuit board inside your remote may be dirty. A thorough examination is usually enough to fix this problem. The most common causes of dirty circuit boards is water and damaged cases. A broken case allows water and other debris to get in and short circuit the electronics. Water can also damage pins and vias, which are tiny connectors found on the board.
If you're able to open your key fob and you don't mind making a mess, we can take the buttons out of their sockets and then solder new ones. Also, it's worth checking the connections between the battery terminals. If they're loose, the buttons may not work or even become stuck in their down position. Soldering terminals and buttons back into place is usually enough to return a malfunctioning fob to a working condition.
Non-Remote transponder chips
Sealed non-remote transponder chips are much more durable than remote fobs they are contained in, but they can be damaged by a hole that is that is drilled into them or over by a lawnmower or door handle for a car. Most of the time, non-remote transponder chips fail, and this could be attributed to an exploded fuse.
If you're not comfortable opening the key fob, remove the circuitboard and utilize a multimeter to determine if the diode is functioning correctly. If you're not 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 sends a signal.
Programming
Key fobs take many abuses and aren't impervious to damage. remote car key repair can lose their pairing to the car's receiver due to shock or low battery, requiring them to be reprogrammed. A professional auto locksmith or main dealer will be able to reprogram your key fob to get it working again. In the event that resetting and repairing your key fob fails, it could be time to replace it entirely.