Today’s vehicles are essentially rolling computers with dozens of...

https://iris-wiki.win/index.php/Why_Does_My_Check_Engine_Light_Keep_Coming_Back%3F_Stop_Clearing_Codes_and_Start_Fixing_Cars

Today’s vehicles are essentially rolling computers with dozens of interconnected ECUs controlling every function. Basic OBD readers only scratch the surface by pulling generic codes, which leaves you guessing at the real root cause