Problem: Since I had the car I've had some problems with the OBC temperature reading. The reading would drop about 10 degrees when the front foglights where turned on. About one year later the OBC temperature reading stayed at -30 Celsius and the check control started giving foglight errors every now and then. Now I was finally fed up with those irritating "dong" sounds...
Solution: In my case the problem was caused by a corroded plug on the bumper wiringloom. The connector is located on the leftside of the car just behind the bumper. It's quite easy to get to from inside the engine compartment on my car. But then again I have a 6 cylinder without the headlamp washing system and thus without an airfilterbox or washertank in the way.
Cleaning the pins with electrical contact cleaner spray solved the problem.
Story by Johan735.