TTT:
// err no, as now, manufacturers are not generally liable for defects that occur during the life of the vehicle. If my brakes fail and cause an accident the maker of the car is not blamed it's down to the driver to make sure the vehicle is safe and roadworthy. //
If the brakes fail, if it is due to a systemic defect, then the manufacturer is liable. If they fail because of poor maintenance then the user is liable. Or it may be a mixture of both, as in the previous BP Deepwater Horizon example.
Software does not degrade over time so any issue with the software is a systemic defect so easy to hold the manufacturer liable if it's a pure software fault. If it is down to the user not maintaining the self-drive system (new sensors for instance) then I'd say in this case as the car has to make so many decisions about whether to start moving or not then it will be easier to hold the manufacturer liable as so many things (e.g. brake performance as it degrades over time) can be measured and reported upon.
If the user subverts systems or does not maintain parts that the self-drive system has no feasible way of detecting - I'll say tyre tread but this is also easy to measure nowadays then it's the users fault.