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Happened to me about 2 years ago. Man, its frustrating; car just stops; no warning. After a few hours, it would run fine for like 20-30 minutes then stop. Luckily, I only had it towed about 25 miles...and to a MBZ dealer too. As Tusabes says : it’s your crank position sensor. The sensor can just die and you're toast!
As far as I know, its unique to the W220 but pretty hard to figure out. The part was like $27 but the labor to figure it out was a lot more. Find a MBZ mechanic that knows the crank position sensor so you don't spend lots of money
 

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But I think he added that the car won’t crank at all. That’s Not the cps.

With a bad cps the car will die out , but will crank when you turn the key - it just won’t fire up .
 

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Hi, @tusabes beat me to it, It will crank until Battery is flat even with a dead CPS ;)

I still say check Pre Fuses first, move on from there ;)
 

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Not unique to the W220; that Crankshaft Position Sensor in anything that uses the M112/M113 engines, the M137 N/A V-12, the M275 TT V-12, and the OM648 TurboDiesel. That means the C-class, E-class, M-class, and S-class. And all of these engines use the same exact type of CPS.

Happened to me a couple of months ago with the '03 S430. We'd stopped to pick up some packages. Got back in and turned the key. Car cranked beautifully, but wouldn't start. Fortunately, we were only about 2.5 miles (about 4km) from home, and I had a spare CPS in the glove compartment, just in case. There is a hardware store in this strip mall, so if I'd had to, I could've just bought the tools (socket wrench, extension, and two sockets) and gotten the job done then and there. But it was a beautiful day, so instead, we walked back to the house, grabbed my tool box, hopped in the truck, and headed back to the S430. Swapped the new one in pretty quickly, and the car's been running great again ever since. The S430 had roughly 155,000 to 157,000 miles on it at that time.

After that, I preemptively did her car, the project 2000 S500, which just clicked 145,000 miles. Also doing to do the S600 TT (175,000) and the E320 CDI (145,000). No need to get stranded when an ounce of prevention will do. :)
 

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"sometimes we have diagnosed starters by smacking them with hammer or pry bar while someone is holding key in start position. Be surprised how often they jolt back to life if only for a short time.good luck "

This usually shows worn or dirty starter motor brushes, and this condition can often be fixed with disassembly and cleaning, with replacement if the brushes are worn out.

Sometimes the CPS will become intermittent - usually working when cold, dies when hot. Some folks have reported that pouring a cold liquid on the sensor will get you running long enough to get to a better place. If I replace an intermittent CPS, it goes in the trunk (along with the 1/4" ratchet, extension and socket need to change it) to get me home from somewhere else. Intermittent can be a lot better than dead...
 

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I keep a spare $8 Chinese cps bought off eBay in the glove box.
LOL I understand your logic, but have you tested it in a Car, I would if I were you .................
I gave up with Chinese / Cheap Sensors long ago, an awful lot of them didn't work outta the box and the rest usually failed within weeks 😉

If it works then great, put it back in glove box, it will likely get you home (y)

HTH,
 

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As an emergency spare, the Chinesium CPS might do OK.

That said, the Bosch ones are only US $25. For twenty-five bucks, I'd just go Bosch.
 

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Don't get me wrong, if you have a whole bunch of MB Cars, I can see the logic in having Chineeseys as a "Get You Home" spare, but I'd want to test every single one before I found out it was a dud at the roadside on a foul night ;)
 

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Does any of you guys have the part number for the bosch one handy?? I would like to buy one as well and just keep it in the trunk. Thanks in advance.
 

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Sure. Here they are, from FCPEuro. Current price: $26.75.

MB part #: 0031532728
Bosch part #: BOS-0261210170
 

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True. Fortunately, though, it's going to be easier to get sockets and a socket wrench from a local hardware store. Even the AAA tow truck should have basic sockets.

That said, I'd just go ahead and replace it if it hasn't already been, or if one cannot confirm that it has been.
 

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T,
I have never done it and I don't know if the previous owner ever did it so like you said, I may just do it as a preventative maintenance and not worry about it.
 

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In virtually all parts of the USA, pawn shops sell used tools. The correct socket, an extension bar and a ratchet or pull handle should be cheap enough to just drop into the spare wheel. And, of course, there is always Harbor Freight...

You might want to tape the parts together to prevent the socket from dropping off of the extension. It is sometime very, very useful to have a small roll of tape in there as well.
 
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