Can't get my Diagnostic Codes. What am I doing wrong ?

Hello all,
I'm an amateur mechanic trying to maintain my 96 corolla 1.6... I've been trying to live with my tight budget and perform the 'easy repairs' I can on my vehicle. I am currently facing a 'check engine light' on and trying to figure out what's wrong. I have 2 questions around computer codes. I need the help from some knowledgeable folks to comment on what I may be doing wrong reading codes.

1) I opened the diagnostic box under the hood, connected TE1 and E1 via paperclip. I turned the ignition to on. I don't start the car. Car is in neutral. All accessories are off. The engine light is on and is not blinking at all like I was expecting it would. It just stays on steady. I can't get any code out of it. What am I missing ?

2) In addition, my understanding is that I will be able to get codes out of it that will look like 21, 42, etc. However, I have seen in some postings that there are codes that look like P00130, etc that can 'come out' of the computer. Can anyone point me to an article or answers as to what the difference is between these codes and the simple one-or-two digit Diagnostic codes. How can I retrieve the more 'complex codes' myself ?

Thanks
A car computer amateur !

Some chain auto parts stores like Autozone will read the codes for free.

obd 1 gives the 2 digit codes, 97 and later, odb2 give 1 letter-4 digit codes... I'll cleck my haynes manual, and get back to you

this site tells you how and what the codes mean

http://www.auto-diagnostic-codes.com/

Thanks for your replies Johnholl ans Sparkeykev.

I haven't managed to get my computer reading to work yet but I'm hoping that I will get it to work with what you suggested. Site looks excellent and I will read the content.

BTW, I found what the problem was on my car. As I couldn't get the codes to come out of the computer, I started examining visually everything I could. Turned out my O2 sensor behind the cat converter was broken in two with the wire hanging loose. I then recalled I had hit a tire debris on the highway the day before. I managed to replace the sensor. Of course I had to struggle with removing the old one as it was seized in place. Hey if you run into engine light on, make sure you do a visual of obvious components and if 'luck' is on your side, it may be something obvious !:grinyes:

Oh forgot to mention. If you do have to replace an O2 sensor behind cat converter, make sure you 'drown' the thread of new sensor in antiseize compound... I wish they did that at the manufacturer with the original sensor.