Modern vehicles are essentially rolling computer networks. When a check engine...

https://tango-wiki.win/index.php/The_Future_of_Diagnostics:_Why_EVs_and_ADAS_Change_Everything_for_Your_Shop

Modern vehicles are essentially rolling computer networks. When a check engine light pops up, your basic code reader only gives you a vague fault code. It can’t see what the ECUs are actually doing or track live data patterns under load