Gone are the days when you could fix every car with a wrench and a test light....

https://josuerwqt559.bearsfanteamshop.com/do-commercial-trucks-use-the-same-diagnostic-approach-as-cars

Gone are the days when you could fix every car with a wrench and a test light. Today’s vehicles are networks of interacting ECUs that control everything from your fuel trim to your door locks