what would be wrong with my car if I can't pick up computer codes through the jack?

[bigcheese1]

I went to get my car inspected, it passed emissions and saftey but when they tried to plug in some machine to check the computer for some reason it wasn't getting a read out. I have a 2001 pt cruiser.

 

[WillS]

Replace the fuse for the cig. lighter, if it's blown, the scanner wont communicate with the vehicle.