OBD2 doesn't tell you much, in a lot of cases. It might identify a loose gas cap or a broken plug wire, but for everything else that can wrong on a modern car you need the manufacturer's proprietary scan tool and a subscription to their online service documents. These cost thousands of dollars, needless to say.

Not that, but certain "luxury-brand" cars specifically don't want you fiddling with anything, and to simply bring it in for a service.

E.g. The weirdest part of it (after driving an old car for the longest time) was they explicitly tell you not to have gas-station attendants check your oil for you. If you're leaking/losing oil, the lights will at some point come on and prompt you to take the car in for service.

> E.g. The weirdest part of it (after driving an old car for the longest time) was they explicitly tell you not to have gas-station attendants check your oil for you. If you're leaking/losing oil, the lights will at some point come on and prompt you to take the car in for service.

Why is that weird? It's a pressurized system with plenty of sensors, you are certainly better off following the data than a gas station attendant (which itself is an old fashioned concept in most places).

>Why? Don't they have OBD-2 readers?

What if they have? It's not like they'd bother to (a) decipher them, (b) fix the issue themselves.

Don't know. The last I met them was about 10 years ago.