Check the pressure in all of your tires. The variance in temperatures could cause the message to appear if your tires are close to the threshold set by the in wheel moniters. My pressure sensors are set at around 60 pounds I believe. I run my back tires at 60 pounds and the front at 65 with no problems when not towing. When the weather got cold here I had to top the pressure off in the rears back up to 60 pounds.