In my jurisdiction, damages from car crashes are strict liability, so you would in fact be legally liable. Limited to ~10 million USD for damages to objects, no limit for damages to persons. Of course the manufacturing defect would give you a credible claim against the manufacturer, but that's a separate matter. Which is why automotive liability insurance is mandatory.

The manufacturer obviously, but they can sell the car in the first place because this defect risk is quantifiable for their liability insurance provider, who can evaluate how risky said car company is in terms of their manufacturing and how likely it is they'll need to pay out a claim, etc.

For self-driving, that evaluation is almost impossible. Sure it can look good statistically, but for things like brake lines, brake pad material, brake boosters, etc, they are governed by the laws of physics which are more understandable than any self-driving algorithm.

You are for failing to check that your car is in drivable state before setting on your journey. This is actual law in my country.