So I was making this 80 mile highway drive one nice spring morning, I get out on the highway and the engine gets up to it's proper temperature as usual. Soon, for some reason, I notice the temp gauge is reading much cooler than it should, the needle was about halfway between cold and normal operating temp. I thought this was peculiar, but it is a turbocharged car with an intercooler, so I thought maybe it just makes it run cooler on the highway at 55mph. Before long, I get the all too familiar chime, and my check engine comes on. I figure this has something to do with the temperature since it happened literally minutes after I noticed it running cold.

So soon I take it to AutoZone to get it scanned, and sure enough, P2181 or whatever for cooling system fault. The new sensor is just $27, but the labor to change it would be significant. Now, the engine has never overheat whatsoever, and the light only comes on when I'm out on the highway, it has yet to come on during city driving so I'm not too worried about it and haven't yet fixed it.