Miller, you got me excited! Went out, held the button, started it up, released the button.... and nothing.
I tried it again when I left the bank, holding INFO instead of RESET. Got the same results, but it didn't reset my tank MPG lol. Since her car is OBD-II (and my S10 is something GM called OBD-1.5) I'll probably just get a 'Gauge for it.
Was worth a try though!