How can I read engine codes?

I have a '91 Storm GSi that runs rough when cold, I want to get the engine codes, is there an easy way to do this? My other car, 1987 Merkur XR4Ti, I can check codes with a voltmeter hooked up the right way and count the needle movements, is there a way to do that with this car?

Look under the passenger lower right kick panel. there sould be on phillips screw and a little bit of pulling. You will see two 3-prong female connectors, an orange one and a white one. The white one is for the engine codes. Take a piece of wire and connect the first and third prong. Turn the key to run (not started) and watch the check engine light. It will flash once and then twice. It will flash 12 three times. then it will flash each stored code three times. When it is done it will flash 12 again. Take a pen and paper, you will need it. Record what you get and look up trouble codes online and you should be able get it from there.

u could read it without pen and paper