I think you have an Iphone? I got this recently:
https://www.amazon.com/gp/product/B01C3HAHCS/
And got this pre-smartphone:
https://www.amazon.com/gp/product/B001LHVOVK/
The former is the way to go with a free software. It does more than the latter. I.e. it reads codes on my ecodiesel RAM.
I installed "Auto Doctor" free.
G