Obd2 scanner differ in function. Some only work as mere trouble code readers, while others can interact with sensors throughout a vehicle. Accessing trouble codes will not turn your check engine light off. Accessing the codes will only tell you the malfunctions the vehicle’s computer has recorded. Codes can be erased with a scanner, but if the problem has not been fixed, the check engine light will always come back on.

Software-wise, my choice for this on Android is Torque, an excellent app that not only can collect all the OBD-II stats, but also graph and log them in myriad ways. (There’s also a free version, Torque Lite, that has a fair deal of the functionality of the full version.) Grab either one from the Google Play store.

Note that this solution is for read-only access to the OBD-II system in the car. You can’t modify the running parameters of the vehicle with this adapter, unfortunately (or fortunately, perhaps, as it’s very easy to make a mess of things). Flashing your car’s computer with a new fuel curve or ignition timing map is a nontrivial exercise that requires an adapter with different voltage levels and different Auto Repair Software. So, don’t worry about breaking your car with this solution—you’re just “peeking under the hood”.

Make sure the vehicle is turned off. Locate the Data Link Connector under the steering wheel. This is an outlet that allows access to the diagnostic computer, which in most vehicles is on the driver side.Connect your Professional Diagnostic Tools to the Data Link Connector. The scanner cable has in a 16-pin plug that should naturally fit into the outlet.Insert your vehicle’s key into the ignition cylinder and switch to “On.” Depending on the brand of OBD-II device, you may also need to turn the engine on and allow it to idle.