YEah, grab one of those Android headunits. Go for one with 2GB of RAM. Then get the Torque app. Then get this OBD2 adapter:
https://www.amazon.com/dp/B01MAURDGG..._B357zbS0PS4CV
The key is to get the "Enhanced Version". This version functions as a Bluetooth Serial Port for Android but also works as a Bluetooth LE adapter for iOS compatibility. If you read the description it says you have to get the WiFi version for iOS compatibility. This is not true. For iOS compatibility you need either the WiFi version OR the "Enhanced Version". They need to update their description. I went with the Enhanced Version because I was really only looking for Android compatibility anyways and I figured what the hell it's only $1 more. When I got it I noticed it was advertizing as "OBD" and "OBD iOS". That is when I realized the description left out the fact that it's also a BLE device. Turns out it will work with the Carista, DashCommand and OBD Fusion. OBD Fusion seems to be the most powerful OBD app for iOS.
Here is a video I shot which shows all the channels supported by Fusion:
[ame="https://www.youtube.com/watch?v=31F3ulaxaLU"]OBD Fusion connected to a 2013 FR-S - YouTube[/ame]
On Android I am using the Torque app which should do what you want on an Android headunit.
Edit: I just noticed the "Enhanced Version" is no longer $1 more but $1 less. So even better. Hahaha