Wont communicate to get codes

Does the battery have enough power so the lights are on in the car when you open the door, dash lights on when you put the key in?

If the battery is fully charged and the scan tool shows a "no communication" message, the cause is usually a computer module that has shorted out and is preventing digital communication on the data bus. Hard to track down yourself. But you can do it with a wiring diagram. Locate all the modules connected to the data bus. Disconnect one at a time until your scan tool can communicate. Once that happens, you'll know which module is causing the problem. Try Alldata.com or eautorepair.net to get a wiring diagram and the location of all the modules.