Having an android OS running hardware box in your car means you can also connect to your vehicles OBD2 with it. The advantage of running the OBD2 app on your headunit is that it can run permanently and monitor the engine in real-time. You can check gas mileage, engine temperature, P code faults, open and closed loop O2 fault finding and much more.
You need a Bluetooth OBD2 adaptor to monitor the engine performance with your android headunit. The adaptor can be permanently connected to the vehicles OBD port with no ill effects to the vehicle but you get all the data.
Use Torque Pro or your favourite android OBD software.
Firstly you must ensure your vehicle is OBD2 compliant. It may have the right shape connector for OBD, but this is no guarantee it will work. The best test is to try a generic OBD reader on the port. Even some later model vehicles are not fully complaint with OBD, so it is best to check first. Even buying a cheap OBD2 adaptor and pairing it with a phone will check for vehicle OBD2 compatibility. If the data flows, the vehicle is compatible with OBD2.
Secondly there are pairing issues with some android headunits and the generic OBD2 adaptors. The headunit asks for a PIN and you can’t enter it or it doesn’t ask for a PIN and won’t pair.
The problem is solved by buying your OBD2 reader from the vendor of the android headunit if there is one available in the listing.
This is the sure fire way to get a compatible OBD bluetooth reader.
You can try your existing OBD bluetooth or buy a generic one, sometimes they work, sometimes they don’t. It is often due to the BT name ‘OBD’ not matching what the headunit wants to see. Sometimes its BT PIN number force problem. But if you are not feeling lucky the best advice is to buy the BT OBD from the vendor of the android headunit if it is listed as an option.