One problem related to power steering pump has been reported for the 2011 Mercedes Benz E Class. The most recently reported issues are listed below.
The contact owns a 2011 Mercedes Benz e-350. While driving approximately 1 mph in reverse the steering wheel became very stiff and difficult to turn. The contact continued to drive the vehicle and the power steering continued to malfunction. The vehicle was eventually towed to an authorized dealer where the contact was told that there was a defect within the power steering pump. The power steering pump was replaced. The failure mileage was 300 and the current mileage was 350.