[JonAvalon]

Originally Posted by BRZtoni

i used this for 2 years no problem. only issue i have is that its kind of long and sticks out a little so you can sort of touch it with your leg..
Amazon.com: BAFX Products - Bluetooth OBD2 scan tool - For check engine light & diagnostics - Android ONLY: Automotive

:edit:
+1 for the BAFX if you're using an Android device, I've been using it the last couple of years with Torque and it's been solid. I paired it with the Carista app you mentioned and it seemed to work although I didn't try anything with it.