... as I was, it may be because the car was sitting idle/parked for 5+ minutes. Turns out the transmitters can align in such a way that the signal won't be received and the timeout, until now, was 5 minutes. There's a firmware update that increases that timeout to 25 minutes. I was encountering this recently because I've been going out to the car to turn on the heat to let it warm up and came back inside to get ready for work. Thought I'd share the knowledge.