I was driving along on our first cold snap, 21 degrees out. I have the Cold Case aluminum radiator in so it takes longer to get up to operating temp and always runs a bit cooler on the guage. So then I get this message in the DIC. Interesting. Then the both fans start screaming and won't shut off. Then the temp guage goes dead. I get home and check a couple of videos and one recommends replacing the wiring pigtail for the CTS. Makes sense since I have 200k on it. So I pick up a new CTS and pigtail and put it on while it's raining out. Nothing changes. I do some more research and one guy says to pull the 10 Amp fuse in number 12 position, the ECM fuse. Wait 10 seconds and put it back in. What do you know? It worked.
Just put about 100 miles on it since then and normal operation.