Here’s a situation where I want an error message and can’t get it. My ’96 Subaru Legacy’s “check engine” light has come on, and some googling suggested that I might be able to retrieve an error code that would tell what is wrong. After reading some instructions and making several trips out to peer under the dashboard, I concluded I was missing a connector. Finally I found the bad news: 1995 was the last year you could retrieve error codes without a “scanner”.

So the modern solution is to leave you with no idea whether it is safe to drive your car to a dealer (77 miles away), or whether it must be towed. Nice.