Yuk, car smells of vomit!

[Ken Sington]

Before we start, no, no-one has puked in it, or on it,and nothing has been spillled inside it, it being an XC90. When the cold weather kicked in, I got a message on the dash computer that said "service engine management system". This is an odd message because it is not one that is listed in the handbook, and the car is a good few '000 miles off it's next service. The message has now gone, but there is a strong vomit like smell around the car. Would this and the message be anything to do with air con or emissions filters perhaps?