How to Repair a Remote Key
Although most remote key fobs have amazing battery lives, they will eventually wear out. Sometimes it's as easy as changing the batteries, however sometimes there are more serious issues.
A quick fix that can aid is to disassemble the remote and cleaning the buttons before stretching them out and in. These methods could be all you need to get the key fob working.
Battery
Car key remotes are powered by CR2025 or CR2032 batteries and they can be swapped out when the fob is functional. If it's not accessible, you can take it off the fob and inspect the buttons and battery terminals for any indication of looseness or broken parts. It is usually possible to solder the buttons and terminals back into place. However, you will be required to know which kind of battery is being used in your fob.
If the battery isn't the issue Try using a backup key fob to see whether you can unlock or start your vehicle with it. If you can do so, it's probably time to replace your primary fob. If not, key repairs will require a professional assess the fob to identify the issue. It could be a simple reconfiguration, or it may require other types of repairs. You may also find that your vehicle has forgotten the fob. This is not something you can fix on your own.
Case Study
The case of a remote key is the plastic case that surrounds it and typically comes with a button pad that is replaced. It is important to use an entirely new case since the original one is likely to be a bit shabby, and it is essential that the circuit board is installed properly in the case. The circuit board controls the key fob's function. You can test it by using a multimeter set to RF (radiofrequency) mode, and a radio scanner that is tuned to the same frequency as the key fob.
Another thing to look at is the button contact points on the keypad, which may have become loose or broken in the course of time. Soldering them back to their original position can often restore them to their original function, unless they snap completely.
Buttons
If your key fob buttons are no longer working or are difficult to push, you can buy an alternative dorman or Motormite remote key housing online for the lowest price for your model/year/make. Then pop the circuit board out of your old case into the new. You may need to alter the position of the circuit board on certain models. Then, you can use aluminum foil using double-sided tape to adhere it to the black contact points on the buttons.
Programming
The key fob and receiver in your car are connected however, this connection may be corrupted. A professional will examine your car to determine its year, make and model. They'll then use specialist equipment to recouple or program a blank transponder chip or fob (or duplicate the key if possible). They will then test the remote to confirm that it works.
It is crucial to be cautious when reprogramming a blank key, as the process can be a bit complicated and different manufacturers require certain steps that are slightly different. It is also easy to miss a step, or take too long to exit the programming mode, which is why it is best to use professionals with extensive knowledge of your car's security system to reduce the chance of damaging your car. Certain programming tools can also be capable of reading diagnostic trouble codes from your vehicle, which can assist in fixing or resolving any other problems.