One problem related to power steering pump has been reported for the 2012 Mercedes Benz S550. The most recently reported issues are listed below.
Vehicle cut on fire while sitting lucky outside, the corner of engine passenger side bellow the headlight stores the suspension air pump and electric hydraulic steering pump. . Base on my inspection the ehps heated and set on fire. Someone saw the car on fire and called fire dept. . Car was lock and store after hours.