The engine may develop a stalling and/or no start condition due to a failed crankshaft position sensor.Google+
Car Problem Reports
Mercedes-Benz S350 Engine Performance Problems Due to Crankshaft Position Sensor Failure
Mercedes-Benz S350 Problem
Model Year Affected: 2006
Average Mileage: 66,000 mi (65,000 mi - 67,000 mi)
Visitor, 2006 Mercedes-Benz S350, 67,000 mi
Car shut off in the middle of driving (very dangerous). The first time the car started right back up after trying. The second time, the car didn't start immediately, had to wait about an hour to restart. Took it to a mechanic and they said it was the crankshaft sensor. Just got it back from the mechanic, let's see how it goes...