Modern vehicles are basically computers on wheels. When a check engine light...

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

Modern vehicles are basically computers on wheels. When a check engine light pops on, a basic OBD reader only gives you a surface-level code, which is like reading the back of a book instead of the story