[rickpilgrim]

There are many code readers and scanners out there, but I will share what I know.If you are just looking to read codes anything from Harbor Freight does that, and they have a 60 dollar one that will read live data, Thats about all the Acutrons and EZ scans that go up to $650.00 do also, with a few more features perhaps. Unfortunately, I havent found anything in the sub $1000(new) that will tell you what could be causing it.
The Snap On Modus we have is a 2006 model we bought used in 2009 with the latest update it was almost 7K. This is a bi directional unit, meaning you can ( even without the keys in) lock and unlock doors, test window and trunk motors, or run any part on the car that the computor contols for testing purposes. It has a built in tutorial so it tells you, step by step how to test things. Ours has the 4 channel labscope on it which is really nice for serious headaches that you would be going to the parts store and replacing this and that untill you found the problem. At the same time thoughthe learning curve is steep, I doubt if I know half of what it can do after 2 yrs and 6 seminars.
Not all Snap On scanners have these features, so do ask many questions before spending cash. BTW, the other day when paying the Snap On bill, the dealer had another Modus just like ours for $3500, and when I asked what ours was worth in trade I was told $1500 of a new top line system which is $11K.
The Only reason we bought this expensiveof a unit is that with 7 trucks, 2 mini(S10) trucks and 2 cars the $99 diagnosis charge was bothering me and the accutronand the EZ scan 5000 and 6000 were just not getting the job done on our stuff
No matter what you end up with it will at least point you in the right direction of where to look.
Just my 2 cents