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2014 E350 W212 (M276) P0346 camshaft position sensor replacement

63K views 49 replies 17 participants last post by  H03victor  
#1 ·
Hi, I just bought a 2014 E350 at ~120K miles. The car ran well for a few months and got a P0346 code with a rough engine and lack of power last week. I have searched high and low to find instructions to replace camshaft position sensor(s) on this W212 (M276) engine. There are articles talking about replacing camshaft sensors, chain tensioners, check valves and camshaft adjuster but I could not find instructions or videos to identify the locations of these sensors and replace them. By chance any one knows any links to any documents or instructions that I can/should use or any service manuals I can buy so I can fix this problem? Thanks a lot for the help.
 
#4 ·
I finally replaced the solenoid y49/4 after breaking 2 bolts!! Cleared code and SEL went away. Car is smooth again.

A lesson learned. I tried to reuse the old bolts thinking 5 NM is not much to worry about. To my big surprise one snapped half way in. So had to wait a few days before new bolts arrive but even one of the new bolt also snapped before I could torque to the spec. Anyone has this problem before?
 
#16 ·
I think you can change the passenger bank one without removing the intake manifold but definitely not the driver side bank ones. Or should I say, if there is a way, I don't know of it and if you go to a shop, they're likely going to take off the intake.

Something to note though...I had my sensors changed on drivers side recently. I had P0346 and it was the only code. I really thought changing sensors would fix my issue. Changing sensors only helped with extended cranking. My car still rattled horribly at start-up, and now I'm replacing the left intake camshaft (it's definitely worn-out) and the camshaft adjuster. Praying this is the solution. I say that to say...it may be the sensor but if you're seeing other symptoms, it may be the camshaft, the adjuster or a combo of the two.
 
#24 ·
This is the part I'm referring to when I say you have the remove the intake manifold to replace the camshaft position sensors. View attachment 2737662

The parts you have labeled as 1 and 2 (camshaft magnets/solenoids) are super easy to replace and do not require removal of intake manifold.
This is the part I'm referring to when I say you have the remove the intake manifold to replace the camshaft position sensors. View attachment 2737662

The parts you have labeled as 1 and 2 (camshaft magnets/solenoids) are super easy to replace and do not require removal of intake manifold.
And where is the 2nd camshaft sensor on the driver side? Thanks.
 
#50 ·
If you ever plan to take off and then take manifold. You better have purchased the new intake gaskets. They are pressure gasket. When you get ready to reinstall if you see any blue on the intake bolts you would have to refresh them and get blue Loctite. The torque is only between possibly 10 to 15 lb but stop at it's a two-step torque process start slow at 7 the blue tightening will start to bond which will give you a different rating of the completion torque. These are notes to look at and understand when using blue Loctite anywhere. And I was told many times to start from Center on both sides outwards. Good luck give me the force be with you.
 
#36 ·
Going to tackle this job next weekend after all of the parts arrive. I have had just over 100K trouble free miles but now have a bad ignition coil so I'll replace all 6 IC and the plugs too. I do see a little oil seepage around timing cover and position sensor/magnets, therefore, will replace all 4 of each and reseal the covers. I figure that I might as well do it all at once, rather than piecemeal. And then hope for another 100K trouble free miles.
The original poster reported that he broke two bolts. My understanding is that these bolts are torqued to 9nm. Not much at all. Correct? Has anyone else had issues with these bolts breaking during this repair? Does the blue paint on the head of the bolt mean that it is a one time use item and should be replace? Before I dive in, I'm wondering if I should pick up a full set of new bolts? Finally, does the WIS call for anti-seize or light lube on the threads? (I have lots of experience on other makes, but this will be my 1st time working on this car.)
Thanks,
-Mike
 
#37 ·
I just had my manifold off of my 2012 E350, Actually had the manifold off twice. You can see notes in the post about timing chain start up rattle under my name West. You may find oil in the manifold when you remove it. If so you will be looking at also replacing the Oil Separator, Crankcase ventilation valve. Some also call this the PCV or positive crankcase ventilation. It sits on the passenger side up against the firewall attached to the head Behind the High Pressure pump. The manifold comes off pretty easy just go slow and find all the attachements, I think there are about 7 wires and hoses that connect to the manifold. The throttle body plug can’t be seen until the manifold is lifted up and there is a vacuum line on the driver side rear that needs to be disconected but removal is only about a 15 minute job. I broke no bolts, I had ordered in extras just in case but did not break any. Be careful as already instructed the bolts with blue paint on the heads tells you they are aluminum and subject to easy breakage. Make sure the threads are clean before install and a little anti seize is not a bad idea. 5nm is not much torque.
 
#38 ·
Removed the manifold, no issues. Tackled the right bank first. Camshaft solenoids, position sensors and front cover all removed with no issues. Cover resealed and everything reassembled and torqued to 5nm. Time consuming but easy. Left bank sensors replaced, everything out of the way, and bolts loosened so that I can tackle the cover and solenoids today.
First bummer is that I need to get a 14mm 12pt deep or spark socket for plug removal. Could have sworn that I had one, but noooooo. All that I have are 6 points! Phoned and visited 3 parts stores and Lowes tool center but no luck.
Second bummer is that there is a little oil in & around the manifold. I really don’t want to tackle the Oil Separator, Crankcase ventilation valve. It looks like a PITA. I’m good a working in the blind, but really hate doing it.
Ugh, so much for an easy quick job!!!!!
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#42 ·
Removed the manifold, no issues. Tackled the right bank first. Camshaft solenoids, position sensors and front cover all removed with no issues. Cover resealed and everything reassembled and torqued to 5nm. Time consuming but easy. Left bank sensors replaced, everything out of the way, and bolts loosened so that I can tackle the cover and solenoids today.
First bummer is that I need to get a 14mm 12pt deep or spark socket for plug removal. Could have sworn that I had one, but noooooo. All that I have are 6 points! Phoned and visited 3 parts stores and Lowes tool center but no luck.
Second bummer is that there is a little oil in & around the manifold. I really don’t want to tackle the Oil Separator, Crankcase ventilation valve. It looks like a PITA. I’m good a working in the blind, but really hate doing it.
Ugh, so much for an easy quick job!!!!! View attachment 2813537
Hi, I'm looking into tackling the sensor under the manifold myself. Are there any one-time use bits such as gaskets that need to be replaced before the manifold can be reinstalled? I also want to avoid disconnecting too much stuff if possible, such as the vacuum hoses in the back, will I be able to remove the bolts and just lift the front of the manifold up to get to the sensor?

Thanks!
 
#39 ·
While the manifold is off look inside the intake ports and see if your valves have build up of carbon on them. A bad case the back of the valve builds up like a tee pee. The carbon build up chokes off your intake and reduces power. The higher the miles the more carbon build up you might have. At 87,000 miles mine had very little.
To replace the PCV is a challenge. The High Pressure pump must be removed and the fuel lines. It is not that hard but it takes time.
 
#40 ·
Well, it only gets better...not! Finished up the left bank...camshaft solenoids, position sensors and front cover resealed with no issues.
Did not want to but figured as long as everything is apart I might as well tackle the Oil Separator Crankcase ventilation valve too. As I was pondering the job I noticed something odd. Huge mouse nest in the valley of the block. UGH!!!! Then noticed a mouse wrapped around a hose (see photo.) Looks like the like the little guy had been there for a while or, maybe this is a Mercedes Engineering feature to soak up oil around the hose fitting? Showed the photo to the dealership parts guy and he said that they didn't stock mice wicks. LOL 😂
I fished out most of the nest before removing the lower intakes bc I didn't want it falling into the heads. What a mess!!! Replaced the Oil Separator Crankcase ventilation valve, new O-ring, gaskets, etc. That was a PITA of a job. Everything back together without a hitch. Oh, and I used orange and pink colored zip ties to re-secure wires. That should make the next mechanic or owner smile and scratch their heads a bit! Overall, as everyone says on this site, it wasn't difficult, just time consuming. It took far more time than I expected or wanted to spent on my daily driver. Hopefully, it goes another 100K of trouble free miles. But if it doesn't, I'll leave the next repair to a local shop.
This site has a lot of great information and thanks to those who provided guidance. Greatly appreciated. After this experience, I think I'd rather spend my time working on my antique rides.
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