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

https://iris-wiki.win/index.php/Choosing_a_Diagnostic_Platform:_Moving_Beyond_the_Generic_Code_Reader

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