Join Date: Sep 2008
Location: Honolulu, HI, USA
The way I know of is to borrow/use a GS-911. Used they might run $250, but they read and reset fault codes and will tell you a lot more. Not everything, but a lot. They also output real-time data to a log file you can look at later, which can be useful.
If someone you know has or can download and install ISTA-D, then get the interface cable (the easiest part) you can access everything (I think) the dealer can. This could also get you in trouble if you change something you shouldn't have.