CakeDaddy

Very helpful thread. Our CLK500 is at the dealer now getting looked for the exact issue (cutting off at stops) Im guessing CPS. I hope it isnt a fuel pump issue. Are new keys the norm for a CPS replacement? Our older CLK320(w208) came with new keys after CPS was replaced.

my thread:
https://mbworld.org/forums/clk-class...-out-stop.html

I'll update my findings here as well if thats ok with the OP. thanks

JimVonBaden

I'm having the same issue with my CLK500. It runs great most of the time, but once in a while, 3 times in the last week, it died at idle. No restart for a while, like 10-15 minutes, then starts and runs fine. It leaves a Check Engine Light when this happens, but goes away after the second restart. I suspect a CPS. I have ordered a Mercedes OBD2 reader, delivered Saturday, and will see what happens. I am assuming the CLK 500 can have the same issue.

My car is a 2005 with 62K miles on it.

Yidney

New keys? No. A CPS is a super-simple sensor - basically the same thing as the the speed sensors on each of your wheels and the cam position sensors. More or less a magnet. What made you think it has something to do with keys?

JimVonBaden

Crank position sensor changed. Hopefully it fixes the issue.

JimVonBaden

Nope didn't fix it.

Is there another sensor, like the cam position sensor, that causes this?

Rudeney

Is it still illuminating the MIL? If so, pull codes and see what it is. Even if the MIL extinguishes after the next start, you will have a stored code.

JimVonBaden

I get a check engine light, no codes according to my iCarsof ti980. The exceptions are a couple of low voltage codes due to killing the battery trying to restart the car repeatedly.

Anker

There's a good chance the low voltage codes are indicating that your battery is going bad. The CEL just indicates that one of the emission control systems has a code. What are the low voltage codes that have been thrown?

Rudeney

If the MIL is illuminated, you have codes. Make sure you scan the ECU/ECM with iCarsoft.

JimVonBaden

If by MIL you mean the check engine light, I do have codes, almost all related to low battery, likely from killing the battery trying to start it. The battery is two months old. Here are the codes. Noe, no code from the ignition modules:

JimVonBaden

I just replaced the Cam Position Sensor. I left the car to idle for 15 minutes and it died again, no restart. This is frustrating because nothing makes sense. When it is running it runs perfectly. Once it dies, it stays dead until the motor cools off.

Rudeney

Those are all "Stored", not "current", so I'd clear them and see f they come back.

Since there are no codes related to anything that would prevent the engine from running, this is either a bad CPS or bad fuel pump. You replaced the CPS, but was it OE? Or at least a Bosch from a reputable seller (i.e. NOT ebay/Amazon)? I'd test the fuel pump: pressure 3.7 to 4.2 bar, power draw 4-9 amps.

JimVonBaden

Both new Bosch. Would a fuel pump run normally, but die at idle and not restart? Seems an odd failure mode.

Rudeney

Honestly, your symptoms are more CPS related, but with no codes, it means "no fuel". A lack of signal from the CPS tells the ECU the engine is no longer rotating so as a a safety feature, it shuts off the fuel pump. Since nothing really went "wrong" - just the fuel supply stopped - there are no codes. Next time it stops and won't restart, pour cold water on the CPS. If that fixes it, then you (still) have a bad CPS.

JimVonBaden

I would love for that to be the issue. What are the odds that I got a bad Crank Position Sensor right out of the box?

Rudeney

Probably very low odds on that, but it does happen. Again, do the cold water thing AND test the fuel pump. If all that fails, then it may be some sort of wiring problem or even a bad ECU.

JimVonBaden

Will do. I doubt the ECU only because that would likely throw a code, right?

CakeDaddy

new keys came with our last crank position sensor replacement.

Rudeney

Keys have nothing to do with the CPS, but a bad key can cause the car to die. I suspect your tech was not a fan of Occam's Razor and instead of going for the least expensive, most likely, and most obvious cause of the problem (CPS), he went for a more expensive, less likely cause (the keys). And once they ordered new keys, the old ones were "overwritten" so you have to get the new ones. I only hope they didn't charge you for all that!

LaciCLK320

The original is on the right. It had 2-3mm thick of silver stuff on top. (Anti seize?) Maybe this caused my issues of no start once in a while. Or was it supposed to be there? It was the original MB part by Bosch. (2005 CLK 320 convertible 56K miles) Replaced it with a Bosch from AutohausAZ. It works fine this time. I will report back in couple of weeks to see if it works or not. Cheers!

JimVonBaden

I've changed mine, twice, and never seen any paste on them.

LaciCLK320

Thanks, Jim! I put the new one in without anything! Not sure how that stuff get there. I am not the original owner. Just bought it couple of month ago.