Not in civil trials, no. Well, they aren't "innocent", they are either liable or not, depending on the preponderance of evidence.

I don't really understand that. How can you sue your car maker for some software fault, if you don't know it was one?

You can sue anyone for anything. A judge can throw it out before an actual trial if there isn't enough evidence to even go to trial though.

So in the end you would have to come up with clear evidence for the failure.