If its a Ford you can pull codes yourself with just a paper clip. I've been doing it for many years. You can go to oldfuelinjection dot com and see how to do it and get a list of 2 and 3 digit codes. I keep a copy of both(2 and 3 digit codes) in my garage and have another to keep in the MH when traveling. Hope this helps.
Bob Kulhanek 2000, 36 ft, Damon Intruder, Ford V-10, 5000 Onan Gen, 2 slides
If it won't budge, hit it harder or get a bigger hammer.