Check codes for 98 voyager

My check engine light came on today. What is the proper way to check the codes.I held down both trip buttons and turned key to start, it did some tests and the last thing my odemeter displayed was code 3
What does this mean.

Take it to the autoparts store, like Autozone, and let them scan those P-xxxx code. It's much simpler and more accurate to get the code....and they do it for free!!

You can go right to the Auto Zone site and look up your specific car...keep in mind that if its a t & c go to chrysler trucks not cars....they have exact diags and specs...I believe that it's the Haynes Bible that you don't have to spend the 15-20 bucks for..just look it up online:)