find the test port box on the engine side of the firewall on the passenger side. there is a flip open cap covering the terminals. use a paperclip to jump between terminals te1 and e1 and then turn the key to the on position without starting the engine. The check engine light will begin to flash. if it flashes quickly and steadily with no break in frequency, then there are no stored codes. Otherwise, it will flash a sequence. count the number of flashes between pauses. a code 25 will blink twice, then pause, then blink 5 more times then a long pause. More than one code can be stored at once, and it will go thru all the stored codes with the oldest logged code first. find the PDF form of the FSM and find the diagnostic code table, and id the codes your computer is showing you. I had a recurring CEL showing me code 25 and 26, which sort of points to O2 sensors. I changed them out with densos and kept getting the same codes even tho they checked out ok. I had a no start coindition a couple weeks back that I chased to bad battery cable terminals. R+Rd the terminals and no more recurring codes. That might not apply to your siutuation, but I include it to show how all things need to be in order in order for all things to be in order.....HTH