Modern cars are basically rolling computer networks. When you only use a basic...

https://dlf-ne.org/beyond-the-code-what-an-advanced-diagnostic-platform-actually-does-for-your-shop/

Modern cars are basically rolling computer networks. When you only use a basic OBD reader, you are just reading the surface layer of a much deeper problem. You need professional diagnostic software to talk to every ECU and see the actual live data stream