Code 4 error (what does it mean?)

I have been trying to look around, even through my manual to see what a Code 4 means before taking it into the dealer as I work during the day and can't bring it in.

No other indicators going on, car still drives fine (came on half way through my commute home today). The only other thing I noticed was that the engine temperature gauge was all the way to cold (25C+ out) though once I pulled into the driveway, turned the car off and on the engine temperature gauge went back to normal but I got the code 4 again.


Thanks for any feedback or help on this.