1996 Lumina codes

Hi everyone. My husband just did an engine swap on our 1996 chevy lumina. It's running fine now but the service engine soon light is on. Does anyone know if and how I can pull the codes. If it's the plug, where is that located? I would appreciate any help! Thanks!

Go to autozone if you have one they will read it free.

Thanks for your reply! My husband knows autozone can do it but he wanted to try and do it himself.

you can if you have an OBD 2 scanner, no the cheap 20.00 one from walmart wont work. I would recomment autozone, or a trusted mechanic. I had that light come on on my 2001 lumina, and I took it to my mechanic, turns out the gas cap wasn't tight, so, he tightened it, and cleared the code, and all is well. If the car runs good, I would just clear the code, and see if it comes back. Do this by pulling the ECM fuse, or diconnecting the batt for 15 secs.