I got this warning on my 05 545i last week. Finally had the chance to have it look at a private shop and they said the thermostat is failing and cost of repair is $302 to be exact. Prior to this warning light, i noticed that when cruising between 30-40 miles per hour, the car would drop speed and rpm feels a little choke or hiccup but at higher speed the car runs fine. This is on regular drive mode. Anyhow, I'm taking the car in to a dealership tomorrow morning and have it diagnosed and see what they find out about the "increased emissions"? I'm not going to tell them about the little choke or hiccup just yet.
Anyone experience the same issue?
Will be posting a follow up soon as possible.