2002 Jeep Laredo

Your engine does not have a return line going back to the gas tank so that is not your problem and if you did nto get this code before taking it into them, I would be suspect that it could have been something they did. If not, then it is a seperate problem that needs addressed. The first thing to check is you Evaporative system under the hood and check for leaks in your lines as well as the round small tank.