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Discussion Starter #1
So I have a 04 Passat V6 and the check engine light is on(which I need off as I'm trying to pass emissions sadly). The 3 codes I get are P0301, P0302, P0303. So far I've replaced the coil, wires, spark plugs, cleaned the MAF and Intake Mani. I've checked the vacuum lines visually as best I could and even took a couple off and reattached to make sure the lines where not defective and all seem pretty ok. What else can I try? What am I missing? When I bought the car it already had an "aftermarket intake" installed if that makes any difference and the check engine light was on but the car ran fine no hesitation or loss of power at all and plus I lived in part of my state that didn't require u to pass emissions to register. But that's all changed and I live in the city limits and need to pass emissions. I've had this problem(and have been aware of these 3 codes) and have been working on it for the past 2 and 1/2 weeks with no luck at being able to get the check engine light to go off. Any ideas on what i should do next?

P.S. it seemed like when I cleaned the MAF sensor the light didn't come back on for a good 15 mins during idle but when I rev'd the car it almost instantly caused the light to come on. Idk if that helps or not
 

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I would start with checking the cam timing with vagcom. Also check the O2 sensor readings. Since the misfires are all on one bank, I would pull the valve cover and check the CCT, both the pads and timing marks.
 

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Discussion Starter #4
Sadly no I don't know much about this car my wife went without me to buy it as I was working so she didn't get no type of history info. Cct? This is going to sound dumb as hell but vagcom? Is that like getting the check engine codes scan by a ob2 scanner(the thing AutoZone does for free to check engine codes). If not where can I find a shop/mechanic that has vagcom? Sorry I'm still fairly new to cars I always worked on civics (don't attack plz it was what my friends and I had and got into)and found them simple I really like this 04 VW Passat V6 (wife loves it cause the heated seats, heated mirrors, etc) and I really want to learn alot more about these cars(really all vw and Audi cars now) I look forward to learning these German made machines.
 

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well you are in the right place as there is a great wealth of information,experience and wisdom regarding Passats especially the B5 platform.
 

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I would start with checking the cam timing with vagcom. Also check the O2 sensor readings. Since the misfires are all on one bank, I would pull the valve cover and check the CCT, both the pads and timing marks.
As PZ suggests this is the most likely of culprits.
All of the misfires are on Bank #1 (passengers side).

All of the work that you have done while it may be a good thing, doesn't really capture the problem.
You need to know what is causing the isolated misfires just on one bank.
That would be the static timing of the cams on Bank #1.
Either the timing belt has skipped/jumped teeth on the exhaust timing pulley.
The CCT pads might worn down/missing.
The CCT might be collapsed
The cam chain might have jumped a tooth on either the intake or exhaust cam.

Vagcom also known as VCDS is a software suite available from HERE.
VCDS software communicates with all of the modules inside the car. It is a crucial tool when difficult diagnosing is needed.
The motto of the earlier days was, if you own a Passat, you need to own Vagcom or VCDS.
At the very least a Bentley manual.
There are other options for scanning software. As an owner of the professional version of the VCDS software, I'm not much in tune as to what the others offer.

I'm curious to know what this 'aftermarket intake' is about. Although this should not be part of the problem.
 

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Discussion Starter #7
The aftermarket intake is just one of the "cones" installed. I noticed when I first got to look at it that the clamps were way to loose and I could hear a sort of a "whistle" leaking air from 1 if them but I tighten that long ago.
Thank you for the info on the VAGCOM or VCDS. I'm going to read all about that after this post.
So I'm guessing that the CCT stands for can chain tension????
I'm very glad I have found this community of Passat owners/enthusiast/DIY/Mechanics/etc. I have already been reading posts like the how to tell between a B5 and B5.5 and other post for an introduction Thanks everyone so far for the help. One last thing so is there an easy way to see visually if the belt did jump to confirm, I'm pretty sure it is as multiple posters on here think it is but want to make sure of course. If it is do I have to replace the whole timing belt (or not replace but go through those steps to fix this problem I read it's very hard)
 

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CCT is cam chain tensioner. The V6 has a timing belt at the front which turns the exhaust cams. The intake cams are linked by a chain and a tensioner under the valve cover that changes the intake cam timing. The plastic pads on these can wear down and even break apart. If they do, the bank that this happens to will show misfires and/or a cam timing code. There have been several people with bent valves when this happens.

Since it is bank one, you do not need to remove the timing belt. Read the writeups for CCT replacement (very similar to the 1.8T) and see if you are up for lifting the intake cam, swapping the pads (or whole CCT) and putting it back together with the proper timing marks.

There is a vag-com locator either in the info forum, or online (just google). I knew one person in ABQ who had one, but he has not been on here for 5+ years.

If you have questions after looking at the instructions, ask more questions. There are probably several Youtube videos available as this engine was used in multiple Audi vehicles and is nearly the same as the 2.7T used in the S4.
 

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CCT could be an issue, but you absolutely want to check the timing belt first. You don’t know when it was changed, which should be every 70K miles / 7 years. Any reputable shop would indicate the belt replacement on the under hood label on the passenger side, or under the timing belt covers, which just clip on/off.
 

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Unlike the 1.8T, the cam sprockets on all of the V6 engines float and need to be cinched down during a timing belt change. (Been there ... done that on a 12-valve and a 2.7T.) Borrow or buy a Schwaben cam lock bar to verify that both banks are in sync with each other and in sync with the crankshaft.
 

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Discussion Starter #11
I've been reading a bit about this job timing belt, cct and I've read that the values bend when the timing belt jumps more than 2 or 3 teeth if that's the case would my car start up and run? When I do start it the misfires are barely noticeable my uncle didn't even hear them tell I said something
 

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Discussion Starter #12
CCT could be an issue, but you absolutely want to check the timing belt first. You don’t know when it was changed, which should be every 70K miles / 7 years. Any reputable shop would indicate the belt replacement on the under hood label on the passenger side, or under the timing belt covers, which just clip on/off.
I will see if there is anything there under the hood or cover
 

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If you bent the valves because of the timing belt being so far off, it wouldn't run.
 

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It could run with 1 bank off due to a bad CCT, but it would not run well. you would know. My 1.8T ran with 2 bad coils, but it could hardly move.
 

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Discussion Starter #15
Sadly I still haven't gotten the problem fix car has been sitting it still starts right up and the misfire in cylinder 1 is hardly noticeable but the check engine light is on still even after trying to reset it to see if it would stay off. So next monday I'm having my buddy replace the timing belt, water pump, and the crankshaft position sensor(pretty sure that's what it's called if I remember correctly), plus the gaskets, etc I'm hoping that this will fix whatever is causing the check engine light to come on or at least we find the problem as he takes it apart. What do u guys think? The timing belt needs to be replace anyways it has like 120,000 miles on it
 

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Well I guess if the timing belt needs to be replaced anyways...
It would be kind of nice to know what is causing problem rather than just throwing parts at it.

Seeing as this has been 5 months since you posted, I'm guessing you've got some time before this car NEEDS to be on the road again.
In one of my posts I mentioned VCDS software. I recommend downloading the free version. A compatible type cable can be had from ebay for cheap. I recommend scanning the car again with VCDS and see what other codes come up, just to be sure you know 100% what your up against.
This is obviously at your own discretion.

With that being said. The codes you're dealing with are isolated to Bank #1 (passengers side). That pretty much rules out spark plugs, plug wires and coils.
It's my guess the crank shaft position sensor is NOT faulty because your dealing with Bank #1 only.
That leaves the static timing on Bank #1 as the culprit. Timing belt could be off on the Bank #1 exhaust cam, the timing chain could be off between exhaust and intake. A severely failed CCT.
Or the timing belt sprocket itself is rotated on the exhaust cam. And lastly, a bad cam position sensor but not likely unless it broken.

Make sure you understand the procedure for static timing 100% before wrenching on the car.
If you have ANY questions, we are here to help.
 

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Discussion Starter #17
So an update I still have my check engine light on. Today my mechanic and good friend finished the timing belt replacement on my 04 Passat V6 also replaced the cam and crank sensor and the serpentine belt as well. The three codes I got now are 17801, 17802, 17803. I'm stumped for the life of me I can't find the problem. So besides the work I listed above I've also replaced the coil pack, new wires, new spark plugs twice, new head gasket, MAF cleaned. What I'm I missing what else can it be. I'm Thankful by the way that we did the timing belt because I thought the belt might have jumped a tooth or two and I was right! Plus the belt was in bad shape and I got the misfire code to go away as well.
 

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Those codes are coil voltage codes, so I would triple check wiring and harnesses going to it, as well as battery and charging voltages.
 

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Discussion Starter #19
Our battery keeps dying from it sitting so long I have to charge up the battery sometimes to start it would that possible be causing the codes?
 

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Discussion Starter #20
OK so now I have a new code that has popped up now with the previous 3 I mentioned the code is P0431 which the code reads:Warm Up Catalyst Efficiency → Below Threshold (Bank2). So this code from what I've read now is most likely due to the Catalytic Converter. Is this now what I'm should be looking at to replace? I still haven't figured out what is causing the other 3 codes either
 
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