Generic OBD readers only tell you half the story. Modern vehicles run on a...

https://wiki-global.win/index.php/The_Professional_Workflow:_What_a_Real_Diagnostic_Session_Actually_Looks_Like

Generic OBD readers only tell you half the story. Modern vehicles run on a complex network of ECUs that manage everything from engine timing to cabin comfort. If you rely on basic codes, you are just guessing