Actually ODBI you can read codes using a wire. Done it on the wifes Mazda. What it does is make the check engine flash in long and short intervals giving you the code number, and cycles through.
'98 (04/98) 540i/6 Biarritz Blue / Sand Beige
Options: 17" Style 32 Staggered / Sport Seats / Xenons / Sport Suspension / 6 Speed / Cold weather Pkg
Mods: M5 Grill, CDV, AE Xenons, Rogue Engineering Octane Short Shifter w/ WSR, Rogue Engineering Performance Transmission Mounts, Royal Purple Synchromax Transmission Fluid, Gruppe M Filter Ram Charger
My Car Site