# Engine Code : 16725 - Camshaft Position Sensor (G40): Implausible Signal



## mj6234 (Jan 24, 2002)

OK, started getting this code recently. Engine was rebuilt 17K miles ago with no issues. Timing belt and tensioner were replaced then. Checked the timing marks on the crank/cam pullies and everything lines up perfect.
We are 99% sure nothing is wrong in the head itself either. We pulled the CPS on a running car and compared the positions of the "fins" underneath the sensor and they were identical between the two cars.
Car has a very hard time starting and has a definite loss of power. Idle is a little rough, and under load it is not happy.
Tried swapping CPS sensors with a working car and didn't make a difference.
If it matters, I have an ATP GT28RS kit with Uni 630 programming.
Any thoughts? I have searched and in most cases it was a timing belt problem, but mine looks 100% perfect....


























_Modified by mj6234 at 9:22 PM 11-10-2008_


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## not SoQuick (Jan 8, 2004)

*Re: Engine Code : 16725 - Camshaft Position Sensor (G40): Implausible Signal (mj6234)*

hmmm I would have done as you did so far








my thoughts would be to maybe check the cam chain tensioner next.When mine finally went kaput I am pretty sure this was the same code too.Was it making any noise?? either way its Simple and free to check it


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## freeborder (Feb 11, 2008)

*Re: Engine Code : 16725 - Camshaft Position Sensor (G40): Implausible Signal (mj6234)*

probably two day ago there was this exact code im sure it could look something like this







this is the thread if you wanna peek http://forums.vwvortex.com/zerothread?id=4087528 but It's cam to cam timing. You don't have to remove the timing belt to fix this, but you will need to compress the chain tensioner


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (freeborder)*

I will see if I can confirm that the cam timing is on. Any other thoughts?


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (mj6234)*

I did pull the valve cover. I guess there is no way to validate that the tensioner is bad or the cams are somehow out of timing. Should there be play in the chain?


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## EF9Si (Dec 12, 2003)

*Re: Engine Code : 16725 - Camshaft Position Sensor (mj6234)*

Welcome to the club i'm still figuring out mine too..


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## EF9Si (Dec 12, 2003)

*Re: Engine Code : 16725 - Camshaft Position Sensor (EF9Si)*

It might be our cam to cam timing, i got a tool to compress my chain link tensioner, but i'm waiting for my buddy to help me out...


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## not SoQuick (Jan 8, 2004)

*Re: Engine Code : 16725 - Camshaft Position Sensor (EF9Si)*

can you post a pic? its tough to explain but the are 2 marks(1 for each cam) when these are up there is a set number of links that should be visable between the cam on the chain.


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## dmust (Aug 19, 2007)

had the same problem on my TT
the intake cam jumped one tooth on the chain, was caused by the broken rail on the tensioner
i replace the tensioner (mucho$$$ and the tool comes with it. re-aligned everything and the problem was solved


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## dmust (Aug 19, 2007)

*Re: (dmust)*

this is off VWHUB (dealer acces only) hope it will help.
The distance between the two arrows on the bearing caps (or between the colored markings) is 16 rollers on the chain. 
The notch on the exhaust camshaft is offset slightly toward the inside in relation to chain roller -1-.


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## mj6234 (Jan 24, 2002)

*Re: (dmust)*

Thx for the pics. The tensioner looks OK on mine. I have one on hand now and am going to have my buddy replace/retime cams as soon as he has a minute. I just don't know what else it could be. Hoping this will fix it.


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## mj6234 (Jan 24, 2002)

*Re: (mj6234)*

OK, I turned things so to arrows on the cam caps point to the markers on the cam gears. When the exhaust arrow is pointing to the marker on the exhaust cam gear, the marker on the intake cam is past the arrow on the intake cam cap (clockwise if you are looking from the driver side). 
The marker is just a little bit past the arrow so that the arrow points just to the left of the marker (not to the left of center of the marker, it misses it entirely).


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_OK, I turned things so to arrows on the cam caps point to the markers on the cam gears. When the exhaust arrow is pointing to the marker on the exhaust cam gear, the marker on the intake cam is past the arrow on the intake cam cap (clockwise if you are looking from the driver side). 
The marker is just a little bit past the arrow so that the arrow points just to the left of the marker (not to the left of center of the marker, it misses it entirely).

I think thats what my cams looks like now, you have to center the marks on the exhaust cam gear on the cam cap notch and and count 16 rollers down to the intake cam side..


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## EF9Si (Dec 12, 2003)

*Re: (dmust)*


_Quote, originally posted by *dmust* »_had the same problem on my TT
the intake cam jumped one tooth on the chain, was caused by the broken rail on the tensioner
i replace the tensioner (mucho$$$ and the tool comes with it. re-aligned everything and the problem was solved

what rails are you talking about?


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*


_Quote, originally posted by *EF9Si* »_I think thats what my cams looks like now, you have to center the marks on the exhaust cam gear on the cam cap notch and and count 16 rollers down to the intake cam side..

So the marks don't line up? Why are they even there if they don't line up?


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## [email protected] (Apr 25, 2007)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
So the marks don't line up? Why are they even there if they don't line up?

When the motor is spinning, the tensioner is extended by oil pressure, and it changes the orientation to dead on. Makes no sense, I know. lol 

_Quote, originally posted by *EF9Si* »_what rails are you talking about?

The phenolic guides that the chain rides on.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
So the marks don't line up? Why are they even there if they don't line up?
Like adam said they move..
Check my thread and what bobziqq said..
http://forums.vwvortex.com/zerothread?id=4096117


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## EF9Si (Dec 12, 2003)

*Re: (EF9Si)*

I'm buttoning up the car now and hopefully this solve my problem.. I hope my chain tensioner is not bad, because it was good when i removed the head..


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*

The tensioner was replaced last night. Exact same symptoms. Any other ideas? Everything looks dead on.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_The tensioner was replaced last night. Exact same symptoms. Any other ideas? Everything looks dead on.
Wow really!! I started my car today and i got the same CEL again.. It took 2-3 cranks before she starts up.. I did everything and what not and still


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*

I'm burning my car to the ground tonight. F this.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_I'm burning my car to the ground tonight. F this.
How many cranking times does it take for your car to start? I noticed your engine is built, did you ever take the crank? I heared if sheared the crank key hole it may jump a tooth.. I never took mine out so i know its good.. Dude it has to be something simple..


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## DonSupreme (Apr 11, 2006)

Are you running aftermarket cams?
Maybe the cam gear slipped a little?


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*


_Quote, originally posted by *EF9Si* »_How many cranking times does it take for your car to start? I noticed your engine is built, did you ever take the crank? I heared if sheared the crank key hole it may jump a tooth.. I never took mine out so i know its good.. Dude it has to be something simple..
















Stock cams. I crank backfire, stop, crank , crank start. Where is the crank key hole. I will look and see if it is in tact.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
Stock cams. I crank backfire, stop, crank , crank start. Where is the crank key hole. I will look and see if it is in tact.
Well, before mine backfires but not it seems like no more back fire its just hard to start... Talking about when you take the crank gear and you should see it..


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*

Could something have gone wrong with the flywheel? Take a look at this one. S4, but had the same codes (for both CPS), tried everything, pulled the tranny and found out something slipped on the flywheel? WTF?
http://www.audiforums.com/foru...19712


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_Could something have gone wrong with the flywheel? Take a look at this one. S4, but had the same codes (for both CPS), tried everything, pulled the tranny and found out something slipped on the flywheel? WTF?
http://www.audiforums.com/foru...19712
WTF! I know 100% sure my car has no any problem except for oil leak on the head gasket.. The day i park the car in the garage and before pulling the head the car started fine and no CEL... I'm pretty sure its not our flywheel or in my case.. Last thing i don't wanna do is pull the tranny out! lol!


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*

I am sure the cam to cam timing is right. Still get the code. Anything else I can check? I am at a loss here.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_I am sure the cam to cam timing is right. Still get the code. Anything else I can check? I am at a loss here.
Yo, i just checked mine and it came out 15 pins only.. I'm moving the intake come 1 tooth it was off a tooth.. This should solve the problem.. Take pics of your cam notch and let see...


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*

Added pics. Marks line up exactly. 16 links. Tried ECU in another car didn't get code. Is there ANY way possible that the cam/crank keyways were damaged but did not break and could be causing the issue? Anyone? Getting desparate here.


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## bobqzzi (Sep 24, 2003)

*Re: (mj6234)*

see if the crank position sensor is loose


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_Added pics. Marks line up exactly. 16 links. Tried ECU in another car didn't get code. Is there ANY way possible that the cam/crank keyways were damaged but did not break and could be causing the issue? Anyone? Getting desparate here.
Check the crank sensor since it correlates with the cam when they move together.. Hopefully you will find the culprit...


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## velocity196 (Feb 19, 2006)

*Re: Engine Code : 16725 - Camshaft Position Sensor (G40): Implausible Signal (mj6234)*

cam timing is off. you need 16 links i think. its been weeks since i had my head apart maybe someone else knows if its 16 or 14.


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## [email protected] (Apr 25, 2007)

*Re: Engine Code : 16725 - Camshaft Position Sensor (velocity196)*

16 http://****************.com/smile/emthup.gif


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## EF9Si (Dec 12, 2003)

*Re: Engine Code : 16725 - Camshaft Position Sensor ([email protected])*

Looking at the mark paint it looks like he has 16 counts..


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (EF9Si)*

Crank position sensor appears to be tight and the wiring is all connected. I guess we are going to take the T-belt off and redo that side.


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## EF9Si (Dec 12, 2003)

*Re: Engine Code : 16725 - Camshaft Position Sensor (mj6234)*


_Quote, originally posted by *mj6234* »_Crank position sensor appears to be tight and the wiring is all connected. I guess we are going to take the T-belt off and redo that side.



































































































Do a complete revolution on the crank.. Make sure it lines up on the notch on the plate cover, make sure the cam line up to the valve cover notch, and check the your cam timing again.. Also, how's your t-belt tension? Tight or loose?


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (EF9Si)*

I have checked the marks 100 times. Everything lines up and is tight. I promise.


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (mj6234)*

OK, new update. All the marks line up, but when they do the pistons are not at TDC. They are on the downstroke. So when you get the pistons to TDC, the mark on the cam pulley is 2 teeth to the left of the valve cover. 
How is that possible? Only if the keyway on the crank pulley failed?


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## EF9Si (Dec 12, 2003)

*Re: Engine Code : 16725 - Camshaft Position Sensor (mj6234)*


_Quote, originally posted by *mj6234* »_OK, new update. All the marks line up, but when they do the pistons are not at TDC. They are on the downstroke. So when you get the pistons to TDC, the mark on the cam pulley is 2 teeth to the left of the valve cover. 
How is that possible? Only if the keyway on the crank pulley failed?
Thats probably your problem.. Usually TDC cyl 1 is up and 4 is up, then 2 and 3 cyl are down. Did you took the crank out when you rebuild your engine?


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## mj6234 (Jan 24, 2002)

*Re: Engine Code : 16725 - Camshaft Position Sensor (EF9Si)*


_Quote, originally posted by *EF9Si* »_Thats probably your problem.. Usually TDC cyl 1 is up and 4 is up, then 2 and 3 cyl are down. Did you took the crank out when you rebuild your engine?

I don't think so. From what I understand, there is only 1 way to put all of this together as the crank pulley only goes on one way. I taking to my buddy's house and he is going to pull it all apart.


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## velocity196 (Feb 19, 2006)

it only goes on one way. My timing was off a little I figured it was either the head being resurfaced or the timing belt needed to stretch into tdc. I don't understand it's not that hard as long as your sure the cams are tdc everything else is simple. you may need to get an adjustable cam gear to tdc it.


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## dubworks13 (Oct 23, 2008)

*Re: (velocity196)*

you need to have cyl 1 on top dead center. Once you have that set put your cams on time. meaning on the marks. 16 links. once you have that set up, you are done put on the belt and crank her up. if you still get these codes you need to check if you are getting signal from the sensor wire harness to the ecm wire harness check for shorts and cont.


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## mj6234 (Jan 24, 2002)

*Re: (dubworks13)*


_Quote, originally posted by *dubworks13* »_you need to have cyl 1 on top dead center. Once you have that set put your cams on time. meaning on the marks. 16 links. once you have that set up, you are done put on the belt and crank her up. if you still get these codes you need to check if you are getting signal from the sensor wire harness to the ecm wire harness check for shorts and cont. 

Right. I think if we just put it all together now again and manually put the pistons at TDC, the marks on the crank pulley/cover will not line up. That is very concerning. Something happened to make them be off.


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## EF9Si (Dec 12, 2003)

*Re: (velocity196)*

You said the car was running good after the rebuild and drove it for 17k miles and now this thing happened, right? Something threw of your timing for sure..


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*


_Quote, originally posted by *EF9Si* »_You said the car was running good after the rebuild and drove it for 17k miles and now this thing happened, right? Something threw of your timing for sure..









Yes. Current theory is something with the crank pulley.


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## dubworks13 (Oct 23, 2008)

*Re: (mj6234)*

if the timing is off on the top and the bottom marks. Remove the head sprocket see if the key pin on the cam sprocket is still intack on the cam i had the same problem at work one time and the sprocket had given out.


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## mj6234 (Jan 24, 2002)

*Re: (dubworks13)*


_Quote, originally posted by *dubworks13* »_if the timing is off on the top and the bottom marks. Remove the head sprocket see if the key pin on the cam sprocket is still intack on the cam i had the same problem at work one time and the sprocket had given out. 

The marks are both off, but off by exactly the same amount if that makes sense.


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## dubworks13 (Oct 23, 2008)

*Re: (mj6234)*

when you have the crank on the bottom mark dead on where is your mark on the sprocket?


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## mj6234 (Jan 24, 2002)

*Re: (dubworks13)*


_Quote, originally posted by *dubworks13* »_when you have the crank on the bottom mark dead on where is your mark on the sprocket?

Dead on, but the pistons are not at TDC. We verified it. When the pistons are at TDC, the marks are both to the left of their corresponding marks on the covers.


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## dubworks13 (Oct 23, 2008)

*Re: (mj6234)*

dam man ok bottom mark dead on and your piston is down at the bottom thats not good.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
Dead on, but the pistons are not at TDC. We verified it. When the pistons are at TDC, the marks are both to the left of their corresponding marks on the covers.
So if they are not TDC how far down is the piston cyl1?


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*


_Quote, originally posted by *EF9Si* »_So if they are not TDC how far down is the piston cyl1?

Not far, but they definitely moved down from TDC. You can feel it when you crank it over by hand if you have something on top of the pistons when you turn it. We used a straw.


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
Not far, but they definitely moved down from TDC. You can feel it when you crank it over by hand if you have something on top of the pistons when you turn it. We used a straw.
So if the crank is line up and if you try to move the crank gear clockwise it will still go up?(hence the TDC position) Bump for updates...


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## mj6234 (Jan 24, 2002)

*Re: (EF9Si)*


_Quote, originally posted by *EF9Si* »_So if the crank is line up and if you try to move the crank gear clockwise it will still go up?(hence the TDC position) Bump for updates... 

No, it is already going down at that point. The piston keeps moving down.


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## DubSix3 (Feb 19, 2002)

*Re: (mj6234)*

The crank pulley had sheared off the key enough to let the pulley slip some but not all the way as is typical in the 2.0s. 
The cam and crank pulley stayed timed to each other just fine, but as Mike stated, in reference to the actual crank TDC, it was off two cam teeth.
If the severed metal buildup had not kept the crank pulley from completely spinning around the crank snub, the head would have been shot.
Here are some pics as the pulley was removed. Big to show the detail of the damage:
















And a pic to compare a new pulley to the failed one. Not much meat there to begin with:


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## EF9Si (Dec 12, 2003)

*Re: (DubSix3)*

I was originally telling to the op that crank pulley might have sheared of the key.. Any updates man?


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## DubSix3 (Feb 19, 2002)

*Re: (EF9Si)*

This is mj6234's engine, the original poster.


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## mj6234 (Jan 24, 2002)

*Re: (DubSix3)*

Everything is (mostly) back together. Test drive around the block yesterday was fine with no misfires or anything else abnormal.
I guess I am the luckiest guy in the world for having the keyway break and not have my head be destroyed.








Case closed. Thanks Hoods Motorsports as always. Always treat me right! http://****************.com/smile/emthup.gif


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## EF9Si (Dec 12, 2003)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_Everything is (mostly) back together. Test drive around the block yesterday was fine with no misfires or anything else abnormal.
I guess I am the luckiest guy in the world for having the keyway break and not have my head be destroyed.








Case closed. Thanks Hoods Motorsports as always. Always treat me right! http://****************.com/smile/emthup.gif 
That was my first hint when you told me everything was line up and all, if you remember that couple threads back i mentioned to you that your crank key might have sheared off.. I'm glad your back man on the road! http://****************.com/smile/emthup.gif


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## [email protected] (Apr 25, 2007)

*Re: (EF9Si)*

Lucky and crazy. At least the frustration will be over soon. lol


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## mj6234 (Jan 24, 2002)

*Re: ([email protected])*


_Quote, originally posted by *[email protected]* »_Lucky and crazy. At least the frustration will be over soon. lol 

Frustration over. Final update. Car runs better than it ever has. I guess I was driving it hurt for a while. It still doesn't make sense how it didn't all just fall apart. Oh well. Happy boosting again.


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## [email protected] (Apr 25, 2007)

*Re: (mj6234)*


_Quote, originally posted by *mj6234* »_
Frustration over. Final update. Car runs better than it ever has. I guess I was driving it hurt for a while. It still doesn't make sense how it didn't all just fall apart. Oh well. Happy boosting again.

Yay for all fixed!


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## ACERS757 (Aug 22, 2011)

*Code 16725 and lacking power!*



mj6234 said:


> _Quote, originally posted by *[email protected]* »_Lucky and crazy. At least the frustration will be over soon. lol
> 
> Frustration over. Final update. Car runs better than it ever has. I guess I was driving it hurt for a while. It still doesn't make sense how it didn't all just fall apart. Oh well. Happy boosting again.


So did this take care of the check engine lamp code 16725 and starting issues? Just curious because I'm experiencing the exact issues...


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