why would my service engine light come on all of a sudden on 1999 GMC Jimmy

just had my 2 front tires replaced and had it aligned

by in Nanticoke, PA on May 17, 2013
1 answer
ANSWER by , May 17, 2013
POSIBLE ITS JUST A COINCIDENCE. HAVE THE CODES READ AND REPOST THEM. WITH THAT INFO MORE HELP IS AVAILABLE.