why does my Audi A4 Quattro's check engine light come on and the engine sputter?

Hi my name is Abraham and I manage Griffin's Auto Repair in Little Italy San Diego downtown. Sorry to hear about your Audi. Losing coolant can cause major problems to your engine if not addressed. At times the reservoir can be fixed, if not it can be replaced. They are usually not to expensive to replace. As for the check engine light being on, a check engine light on can come on for 50 different reasons. It might even be related to the coolant issue. If you like, we can do a courtesy scan to see what codes are present. Feel free to call me at 619-234-7991

don't know.have the code or codes read and post em here.as for the coolant leak from the reservoir,i would suspect it's leaking from the crack.get you a can of the Flex Seal(As Seen On TV).HECK,IF IT CAN SEAL UP CANNON BALL HOLES IN THE BOTTOM OF A BOAT,THEN FLOAT ACROSS A LAKE,THEN A CRACK SHOULD BE EASY TO SEAL.