Need help with crankshaft position sensor
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Joined: Mar 2014
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2005 Mercedes S500, 2005 CLK 320 Convertible
Need help with crankshaft position sensor
While I was driving home from work, my S500 died in the middle of the road. (How embarrassing, right?) It took a couple of tries to get it restarted, but I did make it home. We decided to change the fuel filter which did help some of the sluggishness we had been experiencing. A few days later, it happened again. After researching, we changed the Crankshaft Position Sensor. The car sounded better than when we bought it... until the next morning and it wouldn't start again. Thinking the CPS we bought was bad, I took it back and bought another one in a different brand. Installed and it would start and run... as long as it didn't get over 3500 RPMs. If the RPMs got too high, it would die. Also, if it starting getting hot; in idle or at a red light, it would die. Then, the horrid burning smell started and has not stopped.
So, now, we have a new CPS and the car runs, but will get hot, and the burning smell, which we think may be the alternator. I have ordered one which will be in on Monday.
Today, while messing around under the hood, my husband moved the wiring connector to the CPS and the car died. i restarted it and when he moved the wiring and connector again it died again.
Is it possible for the wiring/connector to be bad? and if so, how do you go about replacing it. I looked online and couldn't find one, then, called the dealer and they don't sell that as a part.
So, now, we have a new CPS and the car runs, but will get hot, and the burning smell, which we think may be the alternator. I have ordered one which will be in on Monday.
Today, while messing around under the hood, my husband moved the wiring connector to the CPS and the car died. i restarted it and when he moved the wiring and connector again it died again.
Is it possible for the wiring/connector to be bad? and if so, how do you go about replacing it. I looked online and couldn't find one, then, called the dealer and they don't sell that as a part.
Junior Member
Joined: Dec 2013
Posts: 18
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From: Dallas
My Wife's 2002 s55; (2) 1971 240z's
I have had the same problem with the wiring to other parts. It maybe at the connector. You will have to wiggle the wires around more to find it. You may need to remove the insulation around the group of wires to get to the crank sensor wires. The wire is probably broken inside the insulation. The wire may look good but broken inside. So you need to pull some on each wire to find the break. Once you find it I like to solder it and use heat shrink for the repair. Hope this helps.
Senior Member
Joined: Jun 2005
Posts: 470
Likes: 20
From: Houston, TX
2017 S63
Running engine will die if the CPS is bad - thats a fact. When CPS fail, they typically suffer from thermal runaway, meaning they get hot and fail, then sometimes they work again when they cool down again. When they are in a hot failed state the engine will crank but not run. This is the typical condition that points to the CPS. There is no check engine code for a failed CPS. "Correction, there is no check engine light but there is a code"
Regarding the engine cutting out after the CPS was changed, it does sound like the connector is not fitted correctly, or there is problem with the pins or wiring near the connector. If you have a smell like that then you should be able to see some evidence at the connector and CPS connector wiring by now. If not then you have something else wrong as well. You need to find the source of the smell I guess.
Regarding the engine cutting out after the CPS was changed, it does sound like the connector is not fitted correctly, or there is problem with the pins or wiring near the connector. If you have a smell like that then you should be able to see some evidence at the connector and CPS connector wiring by now. If not then you have something else wrong as well. You need to find the source of the smell I guess.
Last edited by jnash; Mar 11, 2014 at 01:22 PM.
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MBWorld Fanatic!
Joined: Dec 2012
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From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
Yep, no MIL (Check Engine Light) for the failed CPS, but it does set a code that most, if not all, OBD-II code readers will show - at least on my car. Thanks!
Senior Member
Joined: Jun 2005
Posts: 470
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From: Houston, TX
2017 S63
Yes those water drains on the W220 need to be free and clear, especially the passenger side otherwise water can get into the electronics too easily. There can be a massive amount of water collected ahead of the drain tube on a heavy downpour.
