IIRC, the driver is always liable for the vehicle being operated in an unsafe manner; if this is due to the vehicle systems being maintained in a condition that is unsafe, that's still the driver's responsibility.
If the unsafe condition of the vehicle resulted from a manufacturer's defect, this, again IIRC, generally allows those who experience damages to seek compensation from the manufacturer, but doesn't necessarily relieve the driver of liability (legal liability for any particular harm isn't necessarily exclusive in one party.)
If the unsafe condition of the vehicle resulted from a manufacturer's defect, this, again IIRC, generally allows those who experience damages to seek compensation from the manufacturer, but doesn't necessarily relieve the driver of liability (legal liability for any particular harm isn't necessarily exclusive in one party.)