The CarTrip, recently shown at CES, is part technical advisor and part green meter. Communicating with your iOS device by way of Bluetooth, the CarTrip dongle plug into the ODB-II port in your car, and it seems like its primary function is clearing the “check engine” light that is the annoying bane of most post-1996 cars.

It also displays codes from your car’s inner smart interface, thereby letting you know if there are any ongoing problems. A plant sprout icon inside the app shows how green your car is – meaning how efficiently it’s driving. Even if you don’t have your iPhone or iPad with you, the dongle will still keep a history of your driving and display the results once you reconnect it.

Coming to a car near you in 2011, the CarTrip will cost $90.