OK...this takes some practice to be good at reading codes. It seems hard at first but you'll get the hang of it. OK first off...find the test port. On my 92 SC is on the passenger side near the firewall. Its a little black triangle looking box and it says "EEC test" on it. Pull the cover off to expose the terminals. There should be 5 different terminals and reading from the top left to the right its: 1, 2.....then the next row....3, 4, 5. What you need to do is have the car off. Take a wire or a paper clip and insert one end into terminal #2, and the other end into the single terminal wire. It should be a single wire with a weird looking plug on the end of it. Somewhere in the mess of wires....but in the same wire loom as that EEC test box. Once you find it connect terminal #2 and the single wire with a jumper wire. Now get into the car and turn the key to the "ON" position. If you hook it up right...you should hear the car's fan kick on and off a few times then the codes on the check engine light will begin to flash. This test is called a KOEO test(Key on ENgine off).
Now onto reading the codes. Have a pen and paper ready to write the codes down. They should be 3 digit codes. The first ones that will flash are the hard codes....or what the computer finds thats wrong right now. Each code will flass two times.
OK the tricky part.....each number in a 3 digit code will flash....with a 1 sec pause between digtits. For example: if the code is 234...then there will the two flashes then a short pause.....then 3 flashes....a short pause...then 4 flashes...and then...there will be a 3 sec pause.....and that same code will flash again the same way. Then....after the second time that code repeats..there will be another 3 sec pause.....and a new code will begin to flash. Once the codes are done flashing...there will be a long 6 sec pause.....then one single flash.....which signals the begining of the memory codes which are codes that the computer found eariler and stored in its memory. Read these next codes the same way . After there are no more codes.....then the test is done. Shut the key off. You'll need to clear these codes from the computers memory and to do this....just turn the key back ON, and pull that test wire off while the test is in progress. This clears all the codes.
Make sure you have your car in park...or in neutral(5 speed) otherwise it will give you a code that says to put the car in park/neutral. After you have all your codes writen down. You can do a search online for Ford EEC trouble codes. You should be able to find some website that has a list of all the codes and whats wrong. I dont know any codes offhand except for 111...which is "all systems fine"
I hope this works out for you and i prob. made it sound a lot harder than it really is. It should take about 5 min to do the whole test. Once you get the hang of reading the codes 1 time......it'll be second nature and its a good habit to get into to check the car every once in a while. I'm sure i might have left somthing out...but if you need more help....just write back and i should reply within 20 min. good luck...let me know how it turns out.
