nothing noticalbe is wrong with the system besides the code right?
if so, i'd say it's indicitive of the ATC head going bad. That used to happen in my 1G concorde's ATC. Scanning it would show a code 36, but it worked fine, for like 6 more months.
Either that, or it could be a loss of communciation between the ATC head and the BCM. The only data the ATC needs from the BCM is the outside temp. and the sunload sensor reading.
My first guess would be the head unit failing though. Loss of communcation from the BCM would likely be noticeable in some other system as well.