YOu can comb through the car's operating systems bumper-to-bumper, and still have a surprise breakdown/failure on the road. I experienced mostly unpredictable breakdowns in my old Benz when on the road. Way too many items that may be believed to be sound, which are on their way to failure. You cannot always predict which part(s)/system will fail, and when. BTDT in several old cars over-the-road, and over the years.