W203 -replacing crankshaft sensor


New Member
Aug 24, 2018
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Your Mercedes
clc 180 kompressor 2009
A few notes to help others on this tricky job.

I am hopeful replacing the crankshaft sensor will resolve an issue with the occasional unsolicited shutdown of the engine in this 2009 CLC 180 Kompressor. Descriptions of the job elsewhere point out that it is properly tricky with the sensor sandwiched between bulkhead and engine and retained with one 8mm torx bolt.

1. Remove the 2 under engine splash panels ( 10 bolts)

2. Locate the sensor on the left side of the engine. It can hardly be seen but can be felt with a single cable. First key point is don't try to un-plug the cable. There is little possibility of releasing the plug catch from under the vehicle.

3. Two hands* can just about get into the space around the sensor from below and I recommend spending some time giving your brain some 'touch memory' of the relative locations of the sensor and the retaining bolt.
*mine are size 10 but bricklayers hands may struggle to do this job (ask the wife perhaps :) ).

4. I used a simple tool setup of small ratchet handle and the torx 8mm socket. I have seen suggestions to use extension bars and UJs to get a good access but can't see how such configurations would work in the space available in this car. The head of the ratchet handle cannot be very large in diameter or it will not fit alongside the sensor body. If I added a short extension bar I couldn't get the socket on the bolt head.
IMG_20201006_110329793 (3).jpg

5. Extract the bolt. By keeping one finger on the top of the ratchet and applying a little pressure the bolt came out rather than just moving backwards and forwards. Try not to drop the bolt onto the top of the gearbox!

6. Pull the sensor up from above by its cable and unclip the plug. Replace with new sensor and lower into position.

7. I suggest inserting the bolt into the sensor before locating the sensor into its hole. Place a finger on top of the bolt head and insert the sensor body. The finger will help you locate the bolt into its hole as the sensor slides into its hole.

8. Tighten bolt. Refit splash panels. Took me less than one hour. Fiddly but doable.


Senior Member
Aug 4, 2016
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Sunny Essex
Your Mercedes
W211/E320cdi/2009 and CLK200k 2009
Good job buddy , there are some occasional horror stories about crank sensor replacement , fortunately you dodged them all :D

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