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I have been diagnosing a camshaft position dtc on my 2012 e350 for a little bit now and am ruling it down to the camshaft adjusters. I originally had a code for P0346/P0347 so I first replaced the intake bank 2 camshaft magnet. I also tried switching the new magnet with other magnets. If I recall, the code changed to P0017/P0018 so I replaced all 4 camshaft position sensors and cleaned all the oil out of the wiring. It didn't help and had longer startups. The new sensors had black orings that didn't fit flush like the ones with green orings.
I became aware of the camshaft adjuster issues on the m276 engines and believe that my issue relies here. I disassembled the plenum yesterday to get access to all the intake passthroughs to view the cam adjuster at 53*. From what I could tell, all the camshaft adjusters were lined in the middle of the passthrough except for bank 2 intake (driver (left) side of engine if sitting). It looks a little off but wouldn't say that with 100% confidence. During remove of the plenum, I found a ton of oil sitting in the ecu connector. I cleaned it all out with electrical cleaner and used compressed air to dry.
The code came back after putting everything back (P0346, P0367) but my cheap scanner is telling me that the code is related to bank 1 which would be passenger side although I've read the same code can be for bank 2. I'm most likely going to replace the driver side (bank 2) intake cam adjuster as that is what I see is wrong and it's related to the issue, but would like to hear thoughts from more experienced individuals.
If anyone has the WIS or manual for this, that would help, alongside the videos I've watched. I know theres a tool that locks the bolts down and locks the cam in place, but is that needed?
Side note: The plenum had a ton of oil (about a cup) in it that came out when I tilted it, and noticed the green gaskets were torn so will replace them on the repair. If theres other parts I should replace on the adjuster repair (read to replace the crankcase breather oil drip pan as its easy access, timing chain, and maybe oil check valve, but I believe that needs a special tool as well).
Have a look at connectors for: O2 sensors, injectors and ignition coils. Oil can migrate to those locations. It sounds like your engine harness is saturated.
Have a look at connectors for: O2 sensors, injectors and ignition coils. Oil can migrate to those locations. It sounds like your engine harness is saturated.
Ill check, but I don't believe the problem lies elsewhere since the cam adjuster is visibly not centered through the camshaft position sensor holes. My only concern is if the pulse wheel is shifted but seems like that is only able to be figured out after taking the cam off. I'm going to proceed with replacing the bank 2 intake cam adjuster, timing chain tensioner, and oil check valve.
I understand the reluctor is visible. Does that mean its shifted on the camshaft and the camshaft is no longer "usable". If it has shifted, can I fix it in its original location and get it tac welded to the cam? I have ordered a new camshaft adjuster so will replace that also.
I understand the reluctor is visible.
Does that mean its shifted on the camshaft and the camshaft is no longer "usable".
If it has shifted, can I fix it in its original location and get it tac welded to the cam?
I have ordered a new camshaft adjuster so will replace that also.
The long story short is only CPS removal is needed for correlation troubleshooting.
Saving the expense of new camshafts can be attempted by Resetting bad reluctor wheel to original position (+/- .5mm)
Newer camshafts have positioning marks but not the original ones...
> ADVANCED SAVINGS:
By observing relative position of all 4 locked shafts and markings you can make a good educated guess... the error is not huge, aboutt 1/8In. to 1/4In.
It's significant enough for the computer to pick up the wild timing issue.
-- Rotate crank two turns until...
-- The locked VVT gears are on their timing mark
-- Compare differences of reluctors positions...
How many of the 4x cam.wheels have shifted late ?
Is not directly simple... The normal repair calls for new camshafts.
Last edited by CaliBenzDriver; Mar 22, 2025 at 10:49 PM.
The long story short is only CPS removal is needed for correlation troubleshooting.
Saving the expense of new camshafts can be attempted by Resetting bad reluctor wheel to original position (+/- .5mm)
Newer camshafts have positioning marks but not the original ones...
> ADVANCED SAVINGS:
By observing relative position of all 4 locked shafts and markings you can make a good educated guess... the error is not huge, aboutt 1/8In. to 1/4In.
It's significant enough for the computer to pick up the wild timing issue.
-- Rotate crank two turns until...
-- The locked VVT gears are on their timing mark
-- Compare differences of reluctors positions...
How many of the 4x cam.wheels have shifted late ?
Is not directly simple... The normal repair calls for new camshafts.
Oh man, I did not realize I had to make an "educated guess" re: rotation of the tone wheel. That complicates things for me on my repair, as the tone wheel has to be in correct relative position prior to remarking for cylinder head alignment. That seems a setup for high margin of error and (repeated) failure.
What is the best way to move them back into position? Just with your hand? Screwdriver (I think I read that somewhere)? Must be a more precise method...
Last edited by mdzukunft; Mar 23, 2025 at 01:02 PM.
I will share my personal experience with this, please take it as only my experience. There is absolutely risk with this method. The thing is, the only alternative for me was buying and installing a new camshaft…so I felt I had nothing to lose as the issue had to be resolved one way or another.
You can obtain the specific degrees out of spec via MB code reader, which at least gives you a starting point of reference. Then if you proceed, you go very gently and then retest to see how much if any effect of your taps.
I took my 18” flat blade (big) screwdriver, insert through CPS hole, at an angle, resting behind reluctor wheel tab. Then I took rubber mallet hammer and tapped handle of screwdriver gently. The most important is to not bend/damage the tab, but rather rotate that wheel SLIGHTLY. My own experience was three soft taps in a row, where I felt nothing, nothing, something. Then I read values again and it was within spec just BARELY (-4.5deg or something). Closed it up, cleared codes, and all was well MOSTLY. It threw code and did long start a few times, so I decided to do procedure one more time (3 taps) and moved it about 2 more degrees per scanner. That was 20k mi ago or more and never had the issue return.
Hope this helps, and I can find or take a couple pics to better show what I am describing if needed. Also, plenty of folks would likely advise against this procedure and I can understand why
Last edited by Jaybird123; Mar 23, 2025 at 03:20 PM.
The only issue I have with your method is that I'm already down to the visible camshafts. No way am I going to button her all the way back up to try that method. Maybe if I was starting from scratch (and did not need to replace the VTT anyway).
May be I could place the cam in a vice and do it that way? Although that would be going blind without the degree values...
Maybe I'll just look on eBay for a new camshaft...
I will share my personal experience with this, please take it as only my experience. There is absolutely risk with this method. The thing is, the only alternative for me was buying and installing a new camshaft…so I felt I had nothing to lose as the issue had to be resolved one way or another.
You can obtain the specific degrees out of spec via MB code reader, which at least gives you a starting point of reference. Then if you proceed, you go very gently and then retest to see how much if any effect of your taps.
I took my 18” flat blade (big) screwdriver, insert through CPS hole, at an angle, resting behind reluctor wheel tab. Then I took rubber mallet hammer and tapped handle of screwdriver gently. The most important is to not bend/damage the tab, but rather rotate that wheel SLIGHTLY. My own experience was three soft taps in a row, where I felt nothing, nothing, something. Then I read values again and it was within spec just BARELY (-4.5deg or something). Closed it up, cleared codes, and all was well MOSTLY. It threw code and did long start a few times, so I decided to do procedure one more time (3 taps) and moved it about 2 more degrees per scanner. That was 20k mi ago or more and never had the issue return.
Hope this helps, and I can find or take a couple pics to better show what I am describing if needed. Also, plenty of folks would likely advise against this procedure and I can understand why
JB: this is as close to textbook perfect "bush fix".
No seriously that's all there is to it?
You've used the best procedure short of going the long way for profit.
Figure how much setback you need
Set your own reference marks
Go for it: tap-tap-tap gently.
Measure before, during and after
Imagine the genius who designed the camshafts to use a wheel so lightly pressed it can easily get hammered off position. That's true German precision engineering.
Bad code fixed under 10mn for free: brilliant!
Last edited by CaliBenzDriver; Mar 24, 2025 at 01:17 AM.
The only issue I have with your method is that I'm already down to the visible camshafts.
No way am I going to button her all the way back up to try that method. Maybe if I was starting from scratch (and did not need to replace the VTT anyway).
May be I could place the cam in a vice and do it that way? Although that would be going blind without the degree values...
Maybe I'll just look on eBay for a new camshaft...
You're issue is slightly different. You can not rely on VVT Gear marks because they are unlocked free.
meaning the chain reference is floating in regard to the loose camshaft.
So you can not rotate crankshaft to position camshafts to any trusted position... PITA!!
Did you get any correlation codes?
Plan B replace the parts you need and check timing marks afterwards. Explore tap-tap-tap shortcut to save new camshafts.
You're issue is slightly different. You can not rely on VVT Gear marks because they are unlocked free.
meaning the chain reference is floating in regard to the loose camshaft.
So you can not rotate crankshaft to position camshafts to any trusted position... PITA!!
Did you get any correlation codes?
Plan B replace the parts you need and check timing marks afterwards. Explore tap-tap-tap shortcut to save new camshafts.
I have no timing codes on my current scanner apart from the P0346 which led me to the VTT. And as we commented in my thread, the reluctor wheel looks off in Bank 2’s intake. That’s all I got so far. Wish I had had a better scanner to figure out how many degrees the cam was off before I started the teardown but I didn’t really think that was going to be an issue as I had no timing codes.
I plan to replace the VTT when it arrives on Tuesday. Guess I’ll mark the VTT with the chain in present position although we are in agreement this is likely going to be incorrect as the VTT is unlocked. There’s not really a chance that the reluctor wheel will be in appropriate position when replaced, right? That sounds crazy to me.
if the timing does not line up after reinstall of new VTT, what am I looking at?
As Plan B, I bought a new camshaft on Amazon from a MB dealer so I have 30 days to decide whether to go this route. Even so, how do I know this would even align appropriately with the chain?
I will say, I’ve been where you are and I can agree it’s stressful and confusing. I know I took it all very slowly, as methodically as possible, checked everything 10x and probably doubted myself 100x. It helped me to recognize I was learning a bunch, regardless of outcome, and then when it fired up I was stunned and delighted. Maybe I just got very lucky, who knows. I hope this works out for you too
I got the valve cover off today after spending all yesterday getting the fuel lines and vacuum pump out. I had one t30 left holding the valve cover when I stopped. I removed it today and was able to take the valve cover off.
Well I made a big mistake. After being super careful yesterday to always be at 53* I didn’t check when I removed the valve cover and it was a little past that. The line on the back of the pulse wheel wasn’t flat with the head. Without thinking,
I grabbed my 27mm and started spinning the crankshaft. Well the intake cam walked out of the head. I panicked and reversed the direction, and carefully back it only to find the exhaust cam walking out. I forgot that these cams are held in place by the head and I even bought the kit with the cam locks/pulse wheel marker. I’m left with this. How can I salvage my stupid mistake? Any ideas?
I fixed my mistake and got the cams reseated. Had a helper hold the intake cam while I rotated the crank until the exhaust cam fell back into place!
I proceeded with the removal of the intake cam at 40* tdc after igntion with the laser etchings on the back of the pulse wheel lined up with the head. Replaced the intake cam, adjuster, new chain tensioner and installed the check valve behind the chain tensioner. My marks on the adjusters lined up with the marks I put on the chain and all went well. I buttoned everything up and mocked up the valve cover to see the pulse wheels at 53* tdc.
Well... It seems like the exhaust pulse wheel is to far to the right. I suspect the pulse wheel shifted when the exhaust cam started pressing into the head. I did try to redo the timing to move the chain one tooth to the left on the exhaust cam, however the intake cam adjuster would not fit back onto the intake cam. The intake cam didn't have any markings on the pulse wheel when I inspected it (it's the original) so I suspect that the exhaust cam won't have markings either to inspect if it's shifted. Before I replace the exhaust cam too ($$$), any ideas on what to try or inspect? cam adjusters facing up (marks on chain don't line up since this was after rotating the crank) exhaust cam pulse wheen is a few mm below the head it seems like
I suspect its off by one tooth. Its a few mm off through the sight hole. I tried to move the exhaust cam one tooth to the left but then the intake cam adjuster was not lining up onto the intake cam. This was at 40* after ignition. I may try to rotate 180* and do 40* TDC at overlap.
So I finished… the exhaust wheel ended up shifting so I went to the junkyard and got a used but good exhaust camshaft (checked through cos holes before pulling).
I reinstalled everything and started the car only to find a code and cel. This time it’s p0367 camshaft position sensor b circuit Iow bank 1. Every time I checked through the cps holes the pulse wheels on bank 1 were in the middle. I did hear loud rattling when the car started on that side so I’m thinking it’s a bad cam adjuster?
I even have a video of looking through each hole before I tore down bank 2 but it’s too large for the forum.
I replaced all four cps with genuine bremi and delphi (had ordered ebay ones before) and that has fixed all timing correlated codes. The car has been driving and starting smoothly since. However, I got a new CEL this time on a recent drive for p0137 bank 1 sensor 2 o2 sensor circuit low. I cleaned the ecu plug (little residual saturation from old cps) and the code came back. I will check and clean the o2 sensor plug next but at this point not sure what the actual solution will be to this harness. I replaced this specific o2 sensor about 10000 miles ago for an unrelated issue.
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