If the engine check light is on, what can the dealer see that a tool for $180 can't? For them to check the codes would be $90 + tax. Can they see more or is it worth it to just buy my own OBD reader tool. Do they do pretty much the same thing?
Thanks

yup. as the others said, it will read SOME codes. It will, for instance, take care of that annoying loose gascap code. But it won't, for instance, read the codes when the ABS module goes bad. Kinda disappointing since I went ahead and got one, but since I thought this might happen, I sprung for the autoweb.com setup and can also get my 0-60, 1/4 mile times, and other things. So its not a total loss.

The dealers diagnostic equipment does more than just read codes, it can monitor sensors, run tests and test components too. It also reads EVERY code.
To my knowledge, the aftermarket OBD2 scanners can only read the few codes that the ferderal government requires and that's it. If true, one's then more limited. I've only used the dealer equipment, never any aftermarket stuff so I don't know how usefull those tools are.
One thing to realize, a fault code does NOT always mean "bad part" due to that code so getting a code in itself may not always help you.

His code reader reads out the fault code numbers just like the aftermarket units. If you are somewhat mechanically inclined, a code reader is a good investment. Two uses will pay for it at the usual $80 a pop for the dealer to read them. You won't be able to handle all the problems that it will indicate but a lot of simple, nusiance codes can be taken care of with some reading up on your car plus the vast amount of info on this excellent site.

bl