there are a few threads on the forum about key remote issues etc.
The short of it is this. Pop the key apart and look at the little circuit board inside. Look for corrosion or more common is a broken soldier joint.
If you are good with a soldering iron, and have a fine tip for it, you can retouch all the joints. I did this on my remote along with replacing a micro switch. Works like new
And welcome to forum, I have only been here since December and this place has saved me many times.