P0340 fun

[cmiguel32]

Did some searching. It seems like either:

1. Timing is off by a tooth or
2. CCT pads or tensioner itself is worn

I checked the timing and it seemed spot on. Both cam and crank marks lined up. Full disclosure, I had the newish (5k mile) timing belt off 2.5 weeks ago to do a water pump replacement. No CEL till last night. Manual tensioner seemed fine (nut still tightened to 33 ft lb tq), so I'm not sure if it could've jumped a tooth. I cleared the P0340 code and it comes back on after a minute or two of driving.

CCT is original to the car (150k miles). and the CTS has never been replaced.

I looked at block 93 on VCDS and was getting a -16 value. Was having a hard time following Old Guy's procedure for checking intake cam angle adjustment. I've got a replacement cam tensioner on the way for insurance.

Let me know if i'm missing anything here.

[old guy]

Measuring block 93 will give you your cam phase adjustment. During a cold start cycle the intake cam advances to +22°. Once the cold start cycle completes the cam goes back to 0° advance.

If you check your cam advance with a warm engine at idle MB-93 should read 0° +/- 3°.

During brisk acceleration the cam will advance by 22° and somewhere around 4,000→4,200 rpm the cam advance will go back to 0°.
A P0340 indicates an incorrect allocation which usually means the cam position isn’t reaching full advance or full retard. Consequently you may not get a P0011 or a P0012 where the cam sticks at one end or the other of the full range.

Possibilities: Cam position trigger wheel loose and reading incorrectly. Cam timing off. CCT is sticking and not making it to either end of the range. Low oil pressure affecting CCT operation. I don’t believe worn pads will make enough difference in the cam timing to cause any DTC’s.

[cmiguel32]

Thanks Old Guy! This explanation is helpful.

I'll try to log measuring block to see what it's doing at 4k-4200 rpm.
I haven't gotten any other codes other than the p0340.

Oil was recently changed and the level is at the top.
What's the trigger wheel? The cam gear where the timing belt slips over?

I'm going to double check timing again when I get home. If that still checks out, I'm going to go ahead and replace the CCT.

[old guy]

The trigger wheel is on the front of the intake cam. It is what the cam position sensor utilizes to determine the cam position.

If you watch the cam phase while driving you will need to briskly accelerate. It should start in the non-advanced 0°position and somewhere around 2,000 rpm it will go to a full 22°advance and then around 4,000 it will drop back to 0° advance. If you find that it is hanging up somewhere in between that will confirm that your CCT is sticking.

[cmiguel32]

Thanks!

So watch measuring block 91 and look at the 4th box for these values?

The trigger wheel is on the front of the intake cam. It is what the cam position sensor utilizes to determine the cam position.

If you watch the cam phase while driving you will need to briskly accelerate. It should start in the non-advanced 0°position and somewhere around 2,000 rpm it will go to a full 22°advance and then around 4,000 it will drop back to 0° advance. If you find that it is hanging up somewhere in between that will confirm that your CCT is sticking.

[old guy]

From memory there are several different places you can monitor the actual advance. I will have to confirm when I get home but I believe you can monitor it in block 91 fourth position as well as one of the block 93 positions.

[Bmase]

I am haveing the same problem bought the car like that p/o told me timing belt was done recently haven't had a chance to check it yet Changes the cam ps with a known working one and still having the same issue car runs like a top just have the annoying cel light on all the time.

[old guy]

From memory there are several different places you can monitor the actual advance. I will have to confirm when I get home but I believe you can monitor it in block 91 fourth position as well as one of the block 93 positions.

OK. Apparently my memory sux. Monitor block 90 position three or block 91 position four to read the actual cam position. I just took a spin around the block to confirm. My readings ranged from -1° retard to +23° advance depending upon engine load and RPM.

[cmiguel32]

Thanks. My windows laptop battery died after pulling the codes today in VCDS and right when I started monitoring block 91 (the P0340 was pulled in Motoza)

VCDS is giving me 2 different codes today:

P1340 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28) Incor. Correlation - 002 Lower Limit Exceeded - Intermittent

and

P0012 - Bank 1 Camshaft A (Intake): Advance Setpoint not Reached (Over-Retarded) - 001 Upper Limit Exceeded

Once it's charged I'll monitor block 91 position 4. Before the battery died block 4 was reading -2 at cold start idle.

[cmiguel32]

OK. Apparently my memory sux. Monitor block 90 position three or block 91 position four to read the actual cam position. I just took a spin around the block to confirm. My readings ranged from -1° retard to +23° advance depending upon engine load and RPM.

So I monitored block 90 position three. At idle it reads 1 and between 2k and 4k rpm it only gets up to 6 or 7 and then goes back to 1 past 4k rpms.

[BARRY]

also, when a chain tensioner is about to fail, generally they become noisy.

the 1.8t engine itself when idling isn't noisy at all and should pur like a kitten. if sounds like rubbing, chain noise, diesel sound, clatter, etc, then your chain tensioner is dead.


AHHHH...if you have those two codes in "combination"...chain tensioner is indeed gone...replace it.

[old guy]

So I monitored block 90 position three. At idle it reads 1 and between 2k and 4k rpm it only gets up to 6 or 7 and then goes back to 1 past 4k rpms.

I would think it is one of two things. Either low oil pressure (unlikely) or your CCT is sticking.

[cmiguel32]

I would think it is one of two things. Either low oil pressure (unlikely) or your CCT is sticking.

Yeah probably the CCT. New one arrives tomorrow. **Fingers Crossed**

[old guy]

Yeah probably the CCT. New one arrives tomorrow. **Fingers Crossed**

Good luck! Sure sounds like the problem is a sticking CCT. Be sure to take a close look at the screen on the bottom of the CCT to see if it is clogged. If the screen is clogged you may want to consider cleaning the screen, replacing the pads and putting it back in.

[cmiguel32]

Good luck! Sure sounds like the problem is a sticking CCT. Be sure to take a close look at the screen on the bottom of the CCT to see if it is clogged. If the screen is clogged you may want to consider cleaning the screen, replacing the pads and putting it back in.

Good point. I didn't go OEM with the tensioner and I read about your experience there.

[cmiguel32]

Ended up swapping out the tensioner. CEL is no more. Thanks OldGuy!

[old guy]

Ended up swapping out the tensioner. CEL is no more. Thanks OldGuy!

Glad to hear you got it fixed!

So what brand did you go with? How worn were the pads on the OEM one you took out? What did the screen look like?

[cmiguel32]

Glad to hear you got it fixed!

So what brand did you go with? How worn were the pads on the OEM one you took out? What did the screen look like?

Spoke too soon. CEL is back. Gonna pull the codes later.

[BARRY]

what brand CCT did you purchase? on my most current B6 i replaced the CCT with the cheapest Chinese one I could find...a day later, check engine returned, and after about a month, the CCT was advancing and retarding at all times, and all throttle positions. The replacement was working worse than the original which was also faulty.

replaced last week with a mid priced Chinese one, and works great. Same white box unit with new chain I purchased for my black b6 last year.

most if not all people on the forums state to only use factory parts for the CCT for the reasons i've shared. with non-OEM parts you are taking a gamble.

[cmiguel32]

what brand CCT did you purchase? on my most current B6 i replaced the CCT with the cheapest Chinese one I could find...a day later, check engine returned, and after about a month, the CCT was advancing and retarding at all times, and all throttle positions. The replacement was working worse than the original which was also faulty.

replaced last week with a mid priced Chinese one, and works great. Same white box unit with new chain I purchased for my black b6 last year.

most if not all people on the forums state to only use factory parts for the CCT for the reasons i've shared. with non-OEM parts you are taking a gamble.

I replaced it with one sold by FCP Euro. The CEL I'm getting now is the P1340 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28) Incor. Correlation - 002 Lower Limit Exceeded - Intermittent

I'm not seeing the p0012 anymore.

I'm going to replace the crank position sensor to see if it could be that. Part arrives Wednesday.

[cmiguel32]

Glad to hear you got it fixed!

So what brand did you go with? How worn were the pads on the OEM one you took out? What did the screen look like?

FCP Euro's brand (whichever one that is). The pads were fairly worn, but it didn't look terrible. The screen was clean.

[BARRY]

a buddy of mine said he has heard some things about the FCP euro supplied ones having issues, not sure entirely if they do have problems. I'd possibly recommend you listen to engine noises while you drive. with my faulty CCT's all of them would cause my engine to make rpm up noises at steady acceleration or steady throttle. also would feel like the car was wanting to accelerate and decelerate while i was at steady throttle. i would assume it was the ECU cycling the CCT. the CCT should be quiet at all times...like if it wasn't there.

maybe keep driving if you are unable to figure it out...p0012 eventually will pop up if it is in fact the CCT.

[old guy]

Monitor the cam activity again. You can compare the cam position with the CCT on off switch. As before, you should see the range go from 0 degrees to 22 degrees and back.

[cmiguel32]

Monitor the cam activity again. You can compare the cam position with the CCT on off switch. As before, you should see the range go from 0 degrees to 22 degrees and back.

Did that. Reading on block 93 bank 3 indicated the cam angle was at 20 some degrees = cams mis-timed. I pulled the valve cover, and sure enough intake cam was one tooth forward.
I replaced the crank position sensor and the car idled better than it had in a long time. I think there might've been a combination of things going on. I gotta adjust the intake cam and I should be problem free.

Edit (history for posterity/anyone else who ends up with this issue):

-After replacing cam chain tensioner, I lost the p0012 code, but maintained a P1340.
-After monitoring measuring block 93, I realized the CCT wasn't turning on regardless of rpm/load and the cam angle was at 20 something degrees (indicating cam timing being off)
-Set my engine to TDC last night and verified that the exhaust cam lines up perfectly, however the intake cam is 1 tooth forward = 17 links instead of 16.

Conclusion: I installed the cam chain incorrectly when doing the CCT replacement and the intake cam is 1 tooth advanced.

[BARRY]

awesome...hopefully the belt being off a tooth solves all your problems! on my avant, the car was returned to me from a local shop with the belt off by a tooth as well. 1 tooth retarded. car ran great, passed smog, and i had zero check engine lights for months. upon replacing my chain tensioner i noticed the belt was off a tooth and corrected. car gained like 50hp...it was awesome.

one thing to note is that the alignment marks on the 1.8t engine for the cam is not exact. on all of my B6's the cam gear alignment mark and valve cover alignment mark looked like it was a touch advanced when properly set. definitely not exactly on point to the exact millimeter like a Honda or Toyota engine. had to explain but much closer to the valve cover mark than previously.

[cmiguel32]

Here's a shot of the cams at TDC. Intake cam looks too far to the right.

[old guy]

You may be OK. It's hard to tell from the angle of the picture. Make sure you are aligning 16 links with the cam notches. Ignore the cam cap marks. They just add to the confusion. The cam notches are what control the distance, not the cam cap pointers.

[cmiguel32]

When I look at the cams the links seem dead on at 16. I'll double check.
However, my exhaust cam marker lines up directly with the first link, not offset like the diagram.

If it's not that, then my timing belt is advanced by a tooth by either the belt jumping or keyway damage. The CCT won't even turn on b/c cam 1 is 20 some degrees out.

[old guy]

If the engine starts and runs and the intake cam indicates 20° advance even with the cam activation off I would suspect that the CCT is sticking in the advanced position. Either that or you have an issue with the cam position trigger wheel.

[cmiguel32]

If the engine starts and runs and the intake cam indicates 20° advance even with the cam activation off I would suspect that the CCT is sticking in the advanced position. Either that or you have an issue with the cam position trigger wheel.

How does one inspect the latter? Unbolt it from the front of the intake cam?

[old guy]

Just check to make sure it was installed properly and didn't get bent at some point. There should be an alignment tab to make sure it goes in correctly. Also make sure the bolt is tight.

[cmiguel32]

Just check to make sure it was installed properly and didn't get bent at some point. There should be an alignment tab to make sure it goes in correctly. Also make sure the bolt is tight.

Well I counted the links and there were 16. So the cams are definitely in time. I pulled the metal cam trigger wheel and inspected it. They keyway was fine/reinstalled it.
Still have the p1340 code.

I'm beginning to wonder if I have a shorn keyway on the crank gear. I saw someone else had the exact same issue and that was the problem.

I think i'm going to try swapping the stock CCT back in but with the pads from the new CCT and replace the timing chain. If that doesn't solve it, then I'm pulling the crank bolt/gear.

[BARRY]

Here's a shot of the cams at TDC. Intake cam looks too far to the right.

i'd need to see a lower shot pic so i can see the gear to link engagement to be sure. if you're off by a tooth on the chain tensioner you'd have real funky running issues. the link to tooth engagement is like the photo old guy posted. a little off to the left on the exhaust cam.


my most recent A4 had its crank timing gears keyway sheered off, which caused a valve to piston contact situation. Had this replaced with a new gear as well as the head rebuilt a few months back.

do you have pics of crank TDC alignment, cam gear alignment to valve cover, and lower angle shot of the CCT tooth engagement?

[old guy]

I'm not really clear on your answer to my previous question. What readings do you currently get on the cam advance? Does does it move at all or is it just stuck at 20° advance?

[cmiguel32]

I'm not really clear on your answer to my previous question. What readings do you currently get on the cam advance? Does does it move at all or is it just stuck at 20° advance?

So measuring block 91 box 4 it reads around -1 at idle and as much as +2 under load through the rpm range.
Measuring block 90 box 2 reads OFF and the idle stabilization box 3 reads the same values as above.
Measuring block 93 box 3 idle stabilization reads -23 at idle and as much as -25 under load through 4K and up rpms.

[cmiguel32]

i'd need to see a lower shot pic so i can see the gear to link engagement to be sure. if you're off by a tooth on the chain tensioner you'd have real funky running issues. the link to tooth engagement is like the photo old guy posted. a little off to the left on the exhaust cam.


my most recent A4 had its crank timing gears keyway sheered off, which caused a valve to piston contact situation. Had this replaced with a new gear as well as the head rebuilt a few months back.

do you have pics of crank TDC alignment, cam gear alignment to valve cover, and lower angle shot of the CCT tooth engagement?

I can take some pictures of the alignment to TDC. It's all spot on and now after studying the cam timing diagram so is my cam chain. The car runs and idles normally.

[Believer]

I'm almost certain there are only 15 links between those marks but as previously mentioned the picture isn't ideal.

Sent from my LG-H815 using Tapatalk

[old guy]

So measuring block 91 box 4 it reads around -1 at idle and as much as +2 under load through the rpm range.
Measuring block 90 box 2 reads OFF and the idle stabilization box 3 reads the same values as above.
Measuring block 93 box 3 idle stabilization reads -23 at idle and as much as -25 under load through 4K and up rpms.

Very strange. Here’s what I see at idle. Block 90 and 91 show the cam adjuster OFF and cam angle at 0°. As soon as I start to accelerate the cam adjuster turns ON and in both blocks the cam angle goes to 22°→23°.

Block 93 shows 2° idle stabilization and never moves from 2° even when accelerating. So we need to figure out why your MB93 is reading at the other end of the cam adjustment spectrum.

Dumb question but I have to ask. You have cleared all codes and started fresh, correct?

[cmiguel32]

I'm almost certain there are only 15 links between those marks but as previously mentioned the picture isn't ideal.

Sent from my LG-H815 using Tapatalk

I'll send another picture, but I followed the diagram and made sure each appropriate cam gear notch is being counted to reach 16 links. If it were at 15, wouldn't it run horribly?
The car runs very smoothly throughout the rpm range.

- - - Updated - - -

Very strange. Here’s what I see at idle. Block 90 and 91 show the cam adjuster OFF and cam angle at 0°. As soon as I start to accelerate the cam adjuster turns ON and in both blocks the cam angle goes to 22°→23°.

Block 93 shows 2° idle stabilization and never moves from 2° even when accelerating. So we need to figure out why your MB93 is reading at the other end of the cam adjustment spectrum.

Dumb question but I have to ask. You have cleared all codes and started fresh, correct?

I've cleared the codes, and the p1340 comes back after a few minutes of driving.

[Believer]

I'll send another picture, but I followed the diagram and made sure each appropriate cam gear notch is being counted to reach 16 links. If it were at 15, wouldn't it run horribly?
The car runs very smoothly throughout the rpm range.

Yea it's hard to tell because of the angle. I've been told if it is off a roller, the car will feel sluggish down low. You very may well have 16 between and i just can't tell because of the angle.