Garmin recently published a free- app called "Mechanic" https://market.android.com/details?id=com.garmin.android.apps.mech&feature=search_result In particular, if you have the Garmin EcoRoute HD device that plugs into most newer cars' OBD II port, it can show, via a Bluetooth connection, quite a bit of information about what's going on in your car, including reading and resetting the fault codes that will make your "check engine" light come on. I have the EcoRoute, and have been using it with a Garmin GPS for some time. I got the "Mechanic" app right after it came out. But try as I might, I can NOT get the phone and EcoRoute to pair. I have written Garmin support, and they seemed to imply that there is a known issue with the X. Does anybody here have the EcoRoute, and have they tried Mechanic?