faulty solenoids don't always show up on a scan. I just had a problem where my auto wouldn't select 3rd unless you tricked it by moving the selector from drive to 3rd then back to drive. the auto place ran the scanner and it showed no faults, so they pulled it apart and tested one of the solenoids out of the box. this was faulty and after replacing it all is well. so like some of the others have suggested, the best piece of equipment you can use is someone who knows there stuff.

Didn't show up any thing to do with the solnoids...But showed up that TPS was faulty due to me spraying the enigne bay with water....Durrr lol