I a 94 4X4 pickup with a 22re with about 160000 mile. The original motor had problems so I swapped it for a "new" 22re (115000 miles on it). After I changed the motor the check engine light has always come on. The motor runs fine but I was wondering what was causing the problem. I have seen other posts talking of something that you can do with a paper clip, was just wondering if someone could explain how to do this and find the codes.

 

http://www.ncttora.com/fsm/1993/engine/26diagnosi.pdf