1996 Ford Crown Victoria v8

Question

My 1996 Ford Crown Victoria took it to emissions twice they won't not pass it because of the engine light is on. It's passing all other tests. Took it again and they won't even test it took my vehicle to my cousin's transmission shop hooked it up to a diagnostic test or no codes will show up. Has brand new tires gas cap battery oil change. It runs great. Owned it since 2012 when it's time to take it to emissions is when the light comes on I was calling the Ford company and they would set the code for me before I went to emissions if the $40 is too much for me with my disability benefits. By taking it to them every year could it be used to it and this is why no one can turn it off and why it keeps coming on before its time to take it for emissions