[KnightOwl]

A brain teaser to many mechanics in the NW area. Hopefully, someone has experienced this here before and can shine some light.

Van ran fine until one day at 48k miles, got a check engine light. I used a scan tool and got a P0016 code - Crankshaft position - Camshaft position correlation - Bank 1 Sensor A. Nothing changed in engine performance or overall engine noise except for one minor thing, when the starting the van, the engine cranks for about 3 seconds before it starts. Here's the kicker, when I reset the check engine light, the next time I start the van, it starts right away as it should. The engine light does not come on no matter how long I run the van until I finally restart the van. As soon as I restart the van, the van cranks for 2-4 seconds and starts with a check engine light that pops on a few seconds later.

I tested the camshaft sensors. They tested well. I even bought a new single one and replaced the sensor 1by1/ switched banks with a new one and still got the same "bank 1 sensor A" reading regardless of which bank I inserted the new sensor in.

I talked with about 5 Mercedes mechanics, and they all say the same thing..... BAD TIMING CHAIN OR PULLY OR SKIPPED A TOOTH. I disagreed because to me, that would sound like a mechanical program, and the pro-long cranking would be all the time if it was mechanical. The pro-long cranking shouldn't go away if I reset the check engine light unless the CPU on the car auto adjusts or something. They couldn't deny or agree with what I said. They just basically said it has to do with the timing chain. Also, how can I be so lucky that my timing chain stretches or skips a tooth at around the 50k mark? Some even said it's the oil. I changed the oil TWICE to the recommended mobile one.

So I figure they know better. I went out and broke the bank. I bought a new chain, a new tensioner, and new camshaft sprockets and took it to the mechanic since I didn't have time to do it myself. The mechanic tore everything apart, marked up the locations, and reassembled everything.

Surprise, surprise, nothing changed. P0016 still pops up and in the same method.

I bought a new cranking sensor and told the mechanic to drop it in. He said that the check engine light went away, and he actually started it like 5 different times without any check engine light, but then after 45 minutes of running, the light came back on.

I am lost. Perhaps the chain skipped a tooth, and my mechanic put the chain to old original markings, and it was a skipped position?
I am hoping to have someone here that might be able to shine some light. Not a lot of people are familiar with these 2.0 turbo 4 bangers, although the engine is common. Any pointers would be much appreciated.

 

[Rockster]

The info at this link may be of some help:

P0016 Mercedes-Benz: Code Meaning, Causes, Symptoms, & Tech Notes

This fault code is stored in the engine control module when a synchronization error is detected between the camshaft and crankshaft. The output from both

www.engine-codes.com

 

[KnightOwl]

This is what I got from the dealer scan. We already had the timing chain replaced using the camshaft locking alignment tool. The dealer mentioned that the "intake" side is off by a tooth or two. We moved the timing one tooth, and now the engine runs rough with the same check engine code. We are getting ready to put the chain back on to either the original spot or one tooth in the opposite direction on the intake side. Can someone read this and get a better idea of what's going on? I spent over $700 on this diagnosis, and it's not helping us. Thanks.

 

[Rockster]

This is what I got from the dealer scan. We already had the timing chain replaced using the camshaft locking alignment tool. The dealer mentioned that the "intake" side is off by a tooth or two. We moved the timing one tooth, and now the engine runs rough with the same check engine code. We are getting ready to put the chain back on to either the original spot or one tooth in the opposite direction on the intake side. Can someone read this and get a better idea of what's going on? I spent over $700 on this diagnosis, and it's not helping us. Thanks.

What jumps out at me is I note the tech mentioned finding a broken bolt associated with a magnet. The magnet could be what the camshaft position sensor senses to know the cam timing. If this magnet is loose...

And the tech noted the tensioner was installed incorrectly. That's not good. Finding that suggests someone was in the engine and messed up. If that's the case, any errors in assembly of the cam drive system must be corrected.

It would appear to me the tech was on the right path to getting this sorted.

To state the obvious the camshaft drive system must be in good working order. No broken bolts. No loose magnet. Tensioners must be installed correctly and all chain rails/guides in good condition and secure.

The crankshaft to cam chain relationship must be correct. Then the cam chain must be installed on/over the cam shaft sprockets to ensure the timing is correct. In this regard there is no guesswork involved. The various pieces of hardware, sprockets, chain, have markings that when lined up ensure the timing is correct.

 

[BlauBlitzen2016]

You know, I would have thought it was simply a crankshaft position sensor, because that is what it is a lot of the time. Anyway, the cranking situation would tell me it is almost certainly a computer problem.

 

[KnightOwl]

Thanks for the input @Rockster and @BlauBlitzen2016.

Just to give you a more clear picture, I didn't take my car to a shop to get stripped without first completing the following myself. I tested both camshaft sensors. They tested GOOD and within spec. I still went out and bought 1 new OEM sensor and cleared the code, swapped sensor banks while clearing the p0016 code every time, which did not resolve the issue.

I removed the magnets, tested the magnets, and both tested within working specifications. I tested the input power for both the magnets and camshaft sensors, and both passed.

That's when I ordered brand new camshaft sprockets adjusters, a new chain, new guides, and new tensioner and sent the car to a local mechanic to swap since I didn't have the time. He installed the tool, swapped everything out, and it was still popping the same code.

Then I bought a brand new crank sensor, and he replaced that, and the issue came back after half hour or so of running on and off well.

My mechanic took it apart again to check the timing, all the marks lined up, and nothing jumped. Remember, the car runs great, just getting the check engine and pro-long cranking when ONLY the check engine light is ON. If you clear the code, the engine will start right away, but the following crank will pop the code back after 3-5 seconds of cranking before starting. When started, the engine runs perfectly.

Since he verified all the markings were good, we sent it to the dealer for deep troubleshooting. The dealer might have found the broken bolt, but that was not the root of the issue. When I checked the magnets prior, there were no broken bolts, so either my mechanic broke it or the dealer. So this cant be the issue.

The dealer claim tensioner was installed incorrectly, I think the dealer is on crack. It doesn't make sense. I asked my mechanic, and he laughed. He said it's almost impossible to install the tensor incorrectly. I take his side and not the dealer's because I questioned the dealer if they opened the chain-case, and of course, said no. So I asked if all they did was use a computer diagnostic tool, and they said "pretty much so, yes." What a waste of money.

So we were out of options. Perhaps the clamp tool was off a degree, that's why we decided to skip one tooth and assemble the engine back together. Well now it runs a little rough with the code. So we are planning on putting everything back with the clamp tool. But before we do that, here is my new approach.

The dealer said its the "INTAKE" side that has the issue. I will take off my actual camshaft and see if has two potential issues with it. 1. perhaps it's bent. 2. perhaps the welds failed and the marks slightly moved like in this video. Has anybody experienced this with Mercedes? When I asked my mechanic, he said he has on chevy and Subaru before.

Like they say, 3rd time is a charm. Hoping on this 3rd tare down, we find the issue. If anyone has any more advice, please send them my way. I was thinking of swapping the "camshaft control valve" but it's like $280 for pair. Do you guys think it's worth it? Thoughts?

 

[pounce]

I love your persistence. Really.

Do you know for sure it's not the computer/ECU?

 

[KnightOwl]

I love your persistence. Really.

Do you know for sure it's not the computer/ECU?

Thanks. Well, that's why I paid the big bucks to the dealer to have some awesome 18-year-old kid run the computer thing-ie.. I would suspect they would tell me after they mentioned to me, "it's going to take some extra time to figure this out." I left it for two days at their place. I was willing to pay extra for some answers, but unfortunately, we didn't get far, and I'm stuck on my own. I am hoping the timing marks on the intake camshaft are off. Planning on tearing into the again this week.

 

[Rockster]

Thanks for the input @Rockster and @BlauBlitzen2016.

Just to give you a more clear picture, I didn't take my car to a shop to get stripped without first completing the following myself. I tested both camshaft sensors. They tested GOOD and within spec. I still went out and bought 1 new OEM sensor and cleared the code, swapped sensor banks while clearing the p0016 code every time, which did not resolve the issue.

I removed the magnets, tested the magnets, and both tested within working specifications. I tested the input power for both the magnets and camshaft sensors, and both passed.

That's when I ordered brand new camshaft sprockets adjusters, a new chain, new guides, and new tensioner and sent the car to a local mechanic to swap since I didn't have the time. He installed the tool, swapped everything out, and it was still popping the same code.

Then I bought a brand new crank sensor, and he replaced that, and the issue came back after half hour or so of running on and off well.

My mechanic took it apart again to check the timing, all the marks lined up, and nothing jumped. Remember, the car runs great, just getting the check engine and pro-long cranking when ONLY the check engine light is ON. If you clear the code, the engine will start right away, but the following crank will pop the code back after 3-5 seconds of cranking before starting. When started, the engine runs perfectly.

Since he verified all the markings were good, we sent it to the dealer for deep troubleshooting. The dealer might have found the broken bolt, but that was not the root of the issue. When I checked the magnets prior, there were no broken bolts, so either my mechanic broke it or the dealer. So this cant be the issue.

The dealer claim tensioner was installed incorrectly, I think the dealer is on crack. It doesn't make sense. I asked my mechanic, and he laughed. He said it's almost impossible to install the tensor incorrectly. I take his side and not the dealer's because I questioned the dealer if they opened the chain-case, and of course, said no. So I asked if all they did was use a computer diagnostic tool, and they said "pretty much so, yes." What a waste of money.

So we were out of options. Perhaps the clamp tool was off a degree, that's why we decided to skip one tooth and assemble the engine back together. Well now it runs a little rough with the code. So we are planning on putting everything back with the clamp tool. But before we do that, here is my new approach.

The dealer said its the "INTAKE" side that has the issue. I will take off my actual crankshaft and see if has two potential issues with it. 1. perhaps it's bent. 2. perhaps the welds failed and the marks slightly moved like in this video. Has anybody experienced this with Mercedes? When I asked my mechanic, he said he has on chevy and Subaru before.

Like they say, 3rd time is a charm. Hoping on this 3rd tare down, we find the issue. If anyone has any more advice, please send them my way. I was thinking of swapping the "camshaft control valve" but it's like $280 for pair. Do you guys think it's worth it? Thoughts?

An amazing failure of the cam in that video.

You said something about taking the crankshaft off and checking if it is bent or the cam chain drive sprocket has moved. A bent crank is rare. A test is to lay it in the block on oiled new main bearings and spin it. If it is bent it will not spin smoothly. And you can put a dial indicator on the crank ends to see if there is any movement.

But given that video I think checking the cam shaft sprocket and the crankshaft sprocket for slippage is called for.

 

[Rockster]

Regarding the camshaft control valves while I would not replace these without some clear sign of a problem with them, or an experienced tech advised me to "while there" replace them at this point...

Check the crankshaft cam chain drive sprocket and cam shaft chain sprocket for any slipping out of position.

If they look ok maybe the control valves are worth replacing. Maybe. It is your call of course. I can't say yes but I can't say no either especially if you find no other explanation for the behavior.

 

[Gottlieb]

Some references for checking and resetting baseline cam timing:

 

[Vercingetorix]

I think that the cam cannot be turned on the gear or bent. It would throw an engine misfire code if it was. The camshaft sensor would still read as being ok since in reality it is sensing the timing of the gear, not the camshaft itself. The camshaft could have all its lobes ground off, but the sensor would still read the timing as being ok, because it is sensing gear position.

 

[KnightOwl]

An amazing failure of the cam in that video.

You said something about taking the crankshaft off and checking if it is bent or the cam chain drive sprocket has moved. A bent crank is rare. A test is to lay it in the block on oiled new main bearings and spin it. If it is bent it will not spin smoothly. And you can put a dial indicator on the crank ends to see if there is any movement.

But given that video I think checking the cam shaft sprocket and the crankshaft sprocket for slippage is called for.

Good catch. I totally mislead you. It's "Camshaft" not a crankshaft. I only replaced the crank sensor, but I do not want to tear into the crankshaft whats so ever. At that point, I would go buy a wrecked metris and pull an engine off that. Sad to see this happening on a 50k 274 engine. Just sad.

I think that the cam cannot be turned on the gear or bent. It would throw an engine misfire code if it was. The camshaft sensor would still read as being ok since in reality it is sensing the timing of the gear, not the camshaft itself. The camshaft could have all its lobes ground off, but the sensor would still read the timing as being ok, because it is sensing gear position.

I am sensing the same thing, and I get your logic. My mechanic has seen some strange things and since we have a camshaft balance shop nearby, might as well check. We are limited on options at this point.

Some references for checking and resetting baseline cam timing:

Thank you for that. I have seen this in the manual I bought from eBay. But I will verify whether that's the same instruction that I followed or not. Thanks.

An amazing failure of the cam in that video.

You said something about taking the crankshaft off and checking if it is bent or the cam chain drive sprocket has moved. A bent crank is rare. A test is to lay it in the block on oiled new main bearings and spin it. If it is bent it will not spin smoothly. And you can put a dial indicator on the crank ends to see if there is any movement.

But given that video I think checking the cam shaft sprocket and the crankshaft sprocket for slippage is called for.

That's the disagreement I had with my mechanic. The chain kit came with the bottom crank sprocket. But he told me it's in good shape and doesn't need replacing. So he did not replace the small bottom crankshaft sprocket. He says there is no wear on the teeth. So I convince him to still swap it? If the dealer mentioned the issue is in the skipped tooth on the "intake side" cam, perhaps that's where we should stay focused.

 

[Rockster]

Maybe it is time to really check the cam timing? For my first engine rebuilding I installed an aftermarket camshaft.Of course it came with instructions. I won't say it was a simple job but the cam was compatible with the stock cam drive hardware and all the alignment marks and plated chain links worked.

But I got out my dial indicator, crankshaft degree wheel, and went through the process of confirming the cam timing was right. Also, the cam came with a set of 4 or 5 offset bushings so one would adjust the cam timing either advancing it or retarding it if necessary. I used a couple of different bushings just to see what difference in timing they made. I think I just went with the bushing with no offset.

The 2nd engine rebuild I used a new factory cam. I replaced the crank and cam sprockets, used a new chain. I just went by the markings and the cam timing was fine.

I'd say this would work for you but maybe it isn't for some reason. Certainly if the cam or crank chain sprocket has spun a bit you'll never get the timing right until you finally bring out the parts cannon and happen to replace the defective parts.

 

[KnightOwl]

But I got out my dial indicator, crankshaft degree wheel, and went through the process of confirming the cam timing was right. Also, the cam came with a set of 4 or 5 offset bushings so one would adjust the cam timing either advancing it or retarding it if necessary. I used a couple of different bushings just to see what difference in timing they made. I think I just went with the bushing with no offset.

Rock, I appreciate your responses, I am a little confused. Can you show me the dial indicator degree wheel you used? I know what a dial indicator is, but wondering how you tested the cam, removed or on the head? I'm also not following but "4 or 5 bushings" to adjust the advancing or retarding. Can you send a pic so I know what you are meaning? Thanks.

My mechanic took the intake camshaft off last week. It doesn't have any markings on it. We took it to a camshaft but they didn't find anything wrong with it as they have nothing to compare it to. They will check if it's straight though, but if it's not, I doubt it would cause the mistiming. I ordered a brand new dealer OEM intake camshaft. It will be here next week. I will compare it with my existing one.

 

[Rockster]

Rock, I appreciate your responses, I am a little confused. Can you show me the dial indicator degree wheel you used? I know what a dial indicator is, but wondering how you tested the cam, removed or on the head? I'm also not following but "4 or 5 bushings" to adjust the advancing or retarding. Can you send a pic so I know what you are meaning? Thanks.

My mechanic took the intake camshaft off last week. It doesn't have any markings on it. We took it to a camshaft but they didn't find anything wrong with it as they have nothing to compare it to. They will check if it's straight though, but if it's not, I doubt it would cause the mistiming. I ordered a brand new dealer OEM intake camshaft. It will be here next week. I will compare it with my existing one.

My automotive tools are long gone. I did keep some precision measuring tools, my Snap On 1/4", 3/8" and Craftsman 1/2" drive Snap wrenches, a Snap On precision straight edge. Don't know why. I haven't used any of these in 20 or more years.

The degree wheel looked like this:

Amazon.com

For a dial indicator (stand):

Qnkaa Dial Indicator with Magnetic Base Holder Fine Adjustable Long Arm 0-10mm Professional Gauge 0.01mm: Amazon.com: Industrial & Scientific

Qnkaa Dial Indicator with Magnetic Base Holder Fine Adjustable Long Arm 0-10mm Professional Gauge 0.01mm: Amazon.com: Industrial & Scientific

www.amazon.com

I used a 1" travel indicator with a 0.001" resolution.

IIRC I used the factory directions to line up the crank and cam and installed the chain using the reference chain link and the markings on the sprockets.

This would have sufficed I'm sure but as I said I wanted to actually check the timing.

I'm sorry to say I don't remember the details well enough to give you a step by step on how to do this. There are a number of YT videos that show how this is done.

For my engine I had access to a performance handbook from at least one aftermarket parts manufacturer that specialized in performance parts for the engine and it had a section on how to check the timing/lift of a cam. Besides this I read all I could get my hands on -- this before the internet -- about how to (among other things) check cam timing.

Here's a link to a video that shows the steps of checking cam timing.

The idea is to get the degree wheel set to agree with the crank's position and then rotate the crank by hand -- plugs removed -- and note when the dial indicator -- against a valve -- rises by IIRC 0.050". Then note where the crank's position is in degrees. Now that 0.050" is what is used in the video -- and I don't recall what I used -- but I have to mention the cam maker (M-B) may have a different dimension.

Oh, I wanted to add this: Gottlieb provided some PDFs regarding cam timing checking. I have not looked those over but you should. They probably provide good detail and specifically for the M-B engine and how to check cam timing.

 

[Carsten_MB]

Hi,
I have the same camshaft issue on my 2016 Metris with a little over 100.000 miles on it. It has been to the dealer a total of 3 times and they changed everything including the camshaft itself and the issue is still the same. Check engine light is on.
Did you find a solution to the problem?

 

[KnightOwl]

Hi Carsten, yes I found the issue, I will be updating with images hopefully in next day or two.

 

[pounce]

Oooo... a cliff hanger. I can't wait.

 

[MiasnickMetris]

What was the issue KnightOwl? I am having this same issue with my 2019 Metris that only has 66k miles on it.