95 1.3 check engine light

I just installed used engine in my 95 metro. Seems to run good, but check engine light is staying on. I disconnected battery for 10 minutes and tryed it again, but it is still on. I have an old by-pass tool and code answer book for earlier GM vehicles. Will this work on the GEO, or is there another way. I havent messed with this stuff for 10+ years so I am a little rusty. Thanks for any help!

What year engine did you swap in ? I read on this site that engines from diff. years have different electronics packages. If you post the years some of the gurus like geozuki or crazyinkc may be able to tell you

I swapped in another 95 engine. It is running pretty good, but check engine light still stays on. I cant remember how to check the codes to trouble shoot it.