2007 Volkswagen Jetta unsure what warning light means

I have a 2007 Jetta Wolfsburg edition. When I start the car, a small wrench appears in the area where the mileage normally is. It blinks for a few seconds, and then when the mileage appears, the wrench disappears. This symbol is not listed in the owners manual, and the wrench does not show up in the warning light display area, it shows up below that in the mileage area. I just had the car serviced at 22,000 miles and there are no other warning lights that appear. The car runs fine.