As you have this running for awhile, are you happy with it? Does it run current version of AA? By some chance, are you in the Boston area? Would like to see it in operation.
I mentioned this in the past. If the fob doesn't open the car, take out the battery, wait a second, put it back in. Then you will find the fob working again. I think that works when the battery is somewhat low but I find it works for weeks doing this if you need to do it.