> This annoyed me a little bit. A check engine light is the perfect component for what it does. If it's on it means that something may be seriously wrong and that you're probably too stupid or ill-equipped to fix it.

> If it was something simple, easily detectable and fixable it would have its own light, ie the door is open, you're running out of gas.

I've been in new vehicles with a single light for "low tire pressure". But it wouldn't tell you which tire. Sure, I can discover this by manually reading the pressure on all the tires, but the system has to already know this information. It's just incapable of displaying it.