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

https://kilo-wiki.win/index.php/The_Diagnostic_Divide:_Choosing_Between_OEM_Platforms_and_Generic_Scanners

Modern cars are basically rolling computer networks. When you only use a basic OBD reader, you are just looking at a tiny fraction of the picture. You need deep access to ECUs to see exactly what the sensors are reporting in real time