Hello:
My 2012 e350 with 123000 miles on it suddenly ran rough and the cel came on.I took it to autozone to have the codes read and it returned with p0300 ,p0302 and other misfire codes. The recommendation was to replace the crankshaft position sensor.
I spent hours looking above and below the rear of the engine near the bell housing but couldn't where it is.Has anyone replaced the cps on a m276 engine? Please show me the steps.
Thanks

IIRC it is at about the 2 to 3 oclock position as you are facing toward rear of car at engine/tranny inter face.

Replacing it is not going to fix running rough.

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Jim

Thank you for the tip

We have a pretty good writeup in our DIY tech article section. They mention disconnecting a few hoses to gain access. Check it out:
https://www.pelicanparts.com/techarticles/Mercedes-W204/36-ENGINE-Crankshaft_Positioning_Sensor_Replacement/36-ENGINE-Crankshaft_Positioning_Sensor_Replacement.htm

I don't know why anyone would recommend to replace the CPS for misfire codes. We replace ignition coils just about everyday on the m276 for misfire codes. Find out which cylinder has a misfire and replace the coil.

Yep.,

On the wifes 2014 GLK350 with 282k miles I replaced the crank position sensor at 200k miles as a preventive measure. It is an item that is easy and cheap to replace but will leave you sitting by the road when it fails. My experience has been that they should be good to at least 200k miles.

I agree in regards to the coils too. They are a more common failure item. In the 282k miles I've had to replace one and it had not failed, I needed one for another application in a hurry and took it from the GLK.

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Jim

I have a spare CPS in the glove box in all of my cars.