OBD Fusion from the app store and WiFi OBD module from Amazon. Not alot of info on how to get your iphone to work with the OBD modules so I though I would share what I got to work. You have to add KR as a user defined display.
**********THIS IS A WIFI OBD MODULE**************
http://a.co/d/0djmltY
https://www.obdsoftware.net/software/obdfusion
iPhone WiFi settings page
Once you have the app installed and working you will need to add the User Defined PID KR.