A scan tool is only as good as the hands it's in and even then they cannot tell everything one might need to know. They have NO idea about mechanical failures, but there *may* be clues that can be used to identify a mechanical issue.
Codes are active or inactive, active means RIGHT NOW and inactive means it was in the past - recent or eons ago, it does not know.
Computers are good at identifying current electrical problems on sensors and if you do the output tests, on output circuits as well. But they won't tell you if the oil level is low.
A forum community dedicated to Diesel engine owners and enthusiasts. Come join the discussion about performance, builds, ecodiesel, towing capacity, modifications, classifieds, troubleshooting, maintenance, and more!