Have somebody else run a code check. If you are near an AutoZone, they run it for free. If the code shows something related to the tuneup work, AAMCO has to fix it.
Remember the light can come on for a lot of reasons. I have an Escort. Unbeknownst to me, my gas cap wasn't tightened properly after a gas fill. My light came on. The day after I tightened the cap, it went off. If you have filled with gas, it can be as simple as that.
My light also came on because of a cracked vacuum hose. After I replaced the hose, the light went out immediately.