The engine may develop a stalling and/or no start condition due to a failed crankshaft position sensor.Google+
Car Problem Reports
Mercedes-Benz SL500 Engine Performance Problems Due to Crankshaft Position Sensor Failure
Mercedes-Benz SL500 Problem
Average Mileage: 79,849 mi (30,000 mi - 225,000 mi)
Visitor, 2005 Mercedes-Benz SL500, 61,000 mi
Problem began by exhibiting the "crank but no start" behavior. Was told that perhaps the computer chip in the key was not transmitting correct data and to get a new key. Next it stalled at low speed (approaching a stop sign), and would not restart until approximately and hour had passed. Then stalled again at low speed in a parking lot, re-started 15 minutes later, and then stalled for the last time in the same parking lot. Called for a tow and left it. The car started fine the following morning so was able to get it onto the tow truck and get it to the shop. The crank shaft position sensor was replaced, and so far no more problems.
Visitor, 1995 Mercedes-Benz SL500, 225,000 mi
Starts and runs fine for about 10 mins. Afterward - begins to hesitate and idles roughly. After cutoff - restarting results in choking, coughing, sputtering engine. Sometimes doesn't restart. And stalls at idle when this condition occurs.
after parking and turning off engine, I could not turn the car back on. The car started after cooking off. During drive to mechanic, the car stalled on the road. Diagnosis of crankshaft sensor. $600 repair. Saw a fix on youtube that takes a total of 20 minutes with one tool.
same - cranks - diesels - wont start
I had it replaced.
Visitor, 1999 Mercedes-Benz SL500, 81,000 mi
Car starts up every morning however when I shut it down to go into store, gym, restaurants etc. many times (but not every) it won't start again unless I wait 20 min. or more (sometimes an hour).
Any ideas why?
Takes alot of fun out of driving the vehicle not sure if I go out to dinner if it will be a hassle to get it going again.
Visitor, 2004 Mercedes-Benz SL500, 30,000 mi
Engine would die, then restart after cooling for 15 minutes. Sensor was replaced for $285 and all is well.
Visitor, 1999 Mercedes-Benz SL500, 53,000 mi
Crankshaft position sensor failed resulting in no engine ignition and a flatbed tow to the dealer. evidently this is a fairly common occurence due to age of vehicle.
Visitor, 2003 Mercedes-Benz SL500, 48,000 mi
literally drove the car and parked in municipal parking garage. when I went to get the car out (2 hours later), car wouldn't start and had to have it towed to dealer for repair. luckily I had an extended warranty.
Visitor, 1999 Mercedes-Benz SL500, 75,000 mi
Engine not starting when hot. When engine cooled it started fine..