Hydromo - Very odd...this message seems to stem from way too many causes to be very useful.
Envy - I have multiple pressure gauges as well, and they have always given the same readings within 1 psi, so I doubt my gauges are off. I'm betting the camaro's sensors are wrong.
And my message had not been on in a long while even though the weather dropped into the 50's, but as soon as we hit the 40's it was back on. Still goes away as soon as the weather warms up. I scheduled an appointment with the dealer and sure enough the message didn't come on that day, so I guess I'll wait until it comes back on before I take it in.