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

https://wiki-fusion.win/index.php/Stop_the_%22Parts_Cannon%22:_How_Real_Diagnostics_Save_Your_Shop_Money

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