check engine light on t-100

My check engine light came on. My T-100 has about 80K. I was told on line that you can access the diagnostic code on the ECU with a jumper. Anyone done that? Appreciate knowing what I am dealing with before I take it in to dealer.
Jim

Before going to the dealer, just drive down to any local Autozone. They'll plug it in, tell you the code, and reset for free.

Thanks for the advice!