I'm guessing read codes from the computer. They rattled off the long list with repair prices then said they had to fix all of these first, clear the codes and drive it down the road to see if other codes come up. After I choked over the price and long list I picked up the truck and told them I'd have to save the money before it could be fixed. Came home and did all repairs ourselves except for the o2 sensors. Ran out of money at that point. They also told me I needed front brakes and that the pads were completetly gone and into the rotor which would need replaced, not turned but replaced. Checked on the brakes when we got back home and they have slight wear but no where near worn out.