Modern vehicles are rolling computers where every system talks through ECUs. If...

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 rolling computers where every system talks through ECUs. If you’re still relying on a basic OBD reader, you’re only getting the surface-level trouble codes