* To avoid compatibility issues please make sure the Free version works on your phone before buying.Efficiency is a simple yet powerful trip computer for OBD2 enabled vehicles that is focused on helping you maximize your fuel efficiency. The Pro version allows you to check for Engine Trouble Codes and clear the Engine light.Please report any problems you may encounter. Make sure to include your car model, year, OBD2 adapter, phone model, and Android version you’re using.App Requirements:- A OBD2 enabled vehicle built in 1996 or newer- ELM327 Bluetooth Adapter- An Android 2.1 phone/device or newer with Bluetooth capabilities.Support:For Help visit http://efficiencyapp.wordpress.com/help/ or email to [email protected] Tags: Efficiency, OBD2, OBDII, Elm327, Ecu, MPG, fuel economy, fuel efficiency, Eco meter, ecometer, econmeter, green meter, ECU, car, truck, speed, rpm, gas, OBD, OBD-II.