> a warning message saying "check EV system"
These are some of the most annoying messages a piece of software can possibly display, and I hate them with a passion!
It's like this with a lot of commercial software, where designers don't want to scare users with complicated (useful) error messages, so you just get a "whoopsie! Something went wrong".
I'd much rather have an error message that I _don't_ understand over an error message I _can't_ understand.
In the case of cars, it used to be that a generic "Check engine" light showed up on your dash, and you needed an external tool to ask the computer what caused it to light up, but why would that be nessecary in a modern vehicle? You've got a large, high resolution display (or more!) on the CAN bus, why can't it show the full problem so you could take a picture right as it happens and send it to your dealer for instant diagnosis?
>why can't it show the full problem so you could take a picture right as it happens and send it to your dealer for instant diagnosis?
Fault codes are uploaded to the manufacturer on modern cars with telematics. On mine, the app will say you have an engine fault (or need an oil change or recall) and offer to schedule an appropriate appointment. If you call them, they often have it already in their portal under your VIN. The manufacturer also keeps track of these for regulatory purposes (triggering recalls).
A single fault code doesn't mean much. That's like saying I got a segfault, please fix my problem. You need a stack trace, registers, what the user was doing at the time, whether they can reproduce it, etc.
OBD2 stores a _freeze frame_, most of its readings at the time of the fault. You also need to look at other fault codes, pending codes, frequency/history of the fault to make a diagnosis. In any case, you can't just give one code; it's 5 pages of readings.
I had a similar argument around web-facing feature recently. The question was how much detail to show the consumer on an error indicating the network was down or unreliable.
My stance was that far too many of our support tickets involve someone taking a screenshot, and we'd want that information in any such screenshot... Especially if the network was so bad that it couldn't reach us any other way!
Even if the user error is opaque, why not log a short internal error to flash or the cloud?