Engine Light - Cannot Pass Emission Test

2010 TDi Jetta Waggon
111,000 miles
Timing belt done at 100K
Oil by dealer every 10K


I live in a state that does not allow driving a car that has any error codes in the emissions area. I have an Eng light on full-time. It was on a year ago, so I cleaned the EGR. That put the light out until this past March 1st. My inspection sticker expires today, March 31.

A parts store ran my codes yesterday. They were the same as last year: "EGR and Exhaust Pressure Sensor" is what they told me. I removed and re-cleaned the EGR. Besides being 'clean,' it also functions in that it opens and closes with 12v current applied to the servo motor only.

Returned EGR to car. Still have a light. Replaced the Exhaust Differential Sensor this moring...still have the light.

I have to take it to the VW Stealer today for its sticker, and it will fail. (I love this car, but this is the last rolling computer I will ever own)

The state has no tolerance for anything like this, so I'm screwed.

Any thoughts about this hunk of soot car and its light?

So, why is the MIL on? What DTC(s) does it have?

If you had an EGR flow problem, and cleaning your EGR filter pipe "fixed" something temporarily, you probably need a new DPF. Are your tailpipes sooty inside?

Brand new $75 DPS ... still has the eng light.

The eng light comes on immediately upon key-turn.

These things are garbage!

There are no "bulbs" any longer. They are soldered-on LEDs...very very tiny ones.
In NH, any inspection station must hook it up to a certified computer, and that sends data to the state. That data is recorded along with your VIN. There's no cheating the new-world-order system now.

COdes were cleared by another parts store scanner. Light comes back on.

PLEASE do not take this as a slam, but do any VW Techs read and reply on this board?

I sense a royal screwing coming on from my VW Dealership.

Many knowledgeable people here. You have provided too little info. What were the codes exactly? The codes are a place to start looking not to just change out parts when it points to something. Codes can be looked up here:

http://wiki.ross-tech.com/wiki/index.php/Category:Fault_Codes

and it will usually tell you several things to check.

Not everybody is a daily reader either.

You ignored Oilhammer's question...are you tailpipes sooty inside? Stick your finger in and see. Your DPF could be on the way out

There is a thin layer of soot at the tail. Not big, loose ash like there was in the EGR.

Error code is P0470

One more bit of info.

I removed the hoses from the new DPS. Ran the engine and sealed my finger tips over the hose holes. There was zero pressure or vacuum.

If that tells anyone anything.

You see this thread? http://forums.tdiclub.com/showthread.php?t=344146

Not saying that's what's wrong with your car, but it did fix the same code on the OP's.

Thank you all for all the input. We just found that the parts listings for the DPS claims the computer and DPS need to "get acquainted." I'm heading to the dealer tomorrow to see if they can do this.

I see a .44 magnum slug in this car's future.

ROB357 said:

There is a thin layer of soot at the tail. Not big, loose ash like there was in the EGR.

Click to expand...

You need a new DPF. And you probably already ruined the one new pressure sensor you put on there.

Thanks. What I really need is a 1991 Diesel Wolfsberg that's for sale near me. No bloody computer and no cheesy-arse filter to "make it clean."

One thing to add here... Unless you can somehow go back in time, or if your next new vehicle will be motivated by a four legged hay burner, then computers will be a way of life.

ROB357 said:

Thanks. What I really need is a 1991 Diesel Wolfsberg that's for sale near me. No bloody computer and no cheesy-arse filter to "make it clean."

Click to expand...

And only 52hp.... I know, I put over 400k miles on one. Great little car, but the 2000 Golf I drive every day is much better overall.

This kind of thread mystifies me. Here's a car that is remarkable in its ability to provide power, fuel economy, and good emissions, but it requires some attention and maintenance. The OP's car threw a code a year ago. He chose to clean a component that may or may not have been the cause of the code. It seems safe to assume that whatever else was really faulty may have contributed to the filling of his DPF. Now the car is once again reminding him that there's a problem. And only because he can't pass inspection has he chosen to attend to it. The repair may not be far more expensive than it might have been a year ago. But not he can't ignore it because of the inspection requirement. But it's the car's fault?

Yes, these cars are complex. And yes, repairs can be expensive. But that's the cost for what they deliver. I'm glad we're not driving around in IDI VWs. We wouldn't be able to breathe. And every TDI built is electronically controlled, including my 18 year-old Passat.

You've driven the car 100K miles. Now some deferred maintenance is required. That's the way it goes. If you don't like that, you probably should trade it in.

Not unusual. From the NHTSA investigation closing report it stated that of those who said they got no warning before failure, 100% of them did get one for 1 to 60 miles worth. This from examining the data on the cars themselves. People don't take notice or don't stop driving until the car fails. In the past you could drive around with the check engine light on with little to no issues, today this isn't a good idea. Stop and fix the issue now.

Sounds like the dpf cracked causing the first code, cleaning the filter just delayed the inevitable.

Not much the op could of done different.

VarmintSlayer said:

Sounds like the dpf cracked causing the first code, cleaning the filter just delayed the inevitable.

Not much the op could of done different.

Click to expand...

Except fixed it correctly in the first place. The DPF was cracked. EGR filters do not "clog up" on their own.

There is a TSB about this. Kinda old news by now.

It sucks, but that's what the root problem is. Clogged EGR filter and sooty tailpipes are both symptoms of a cracked DPF. Period.

I have a 2011 JSW here now like that. Except he decided to keep driving it, now 20k miles later, it ALSO needs the catalyst, because the soot from the non-functional DPF ruined the catalyst, too!

Went to the dealer today. Their reader showed two exhaust pressure sensors being bad. They replaced both for $400. Then they came back and said it must be the DPF. They wast $2000 for that.

As for history??? I responded to the error codes it threw. that is, it said EGR Valve had an issue. There are LOTS of clogged EGR valve posts here and everywhere. I cleaned it. It worked. Light went out. What MORE could I have done for it? How can you possibly claim this was caused by neglect?

These things are nightmares on a grand scale. But living in a police state that requires the little light be out makes it so much worse.

Another question. Can it really be the DPF if the car is running very strong and efficiently?

BTW: Don't know if you all have already seen this, but I found it last night and it seems really helpful in beginning to understand this beast. One of the best produced manuals I've ever seen.

http://www.natef.org/natef/media/natefmedia/vw%20files/2-0-tdi-ssp.pdf

ROB357 said:

Went to the dealer today. Their reader showed two exhaust pressure sensors being bad. They replaced both for $400. Then they came back and said it must be the DPF. .

Click to expand...

Your dealer is staffed by morons. The cracked DPF problem had a TSB issued OVER A YEAR AGO, and has even been updated (to include newer cars) later on.

The EGR flow problem is a SYMPTOM of the cracked DPF. You needed (past tense) a new DPF as soon as you found a clogged EGR filter the first time. I cannot make it any clearer than that.

Had you checked here, you would have maybe found this out ahead of time, not sure. I don't know when your first had the problem. Again, your dealer SHOULD know this. If they don't, they should be slapped in the chode. LOTS of these cars have the same problem. It is VERY common. We replace DPFs all the time now, and more and more as these cars mile up.

BTW, the TSB even has pictures, so even if the dealer tech is an illiterate knuckle-dragger, he could STILL get the basic idea of what is going on.

This thread.

http://forums.tdiclub.com/showthread.php?t=425077

PowerslavePA said:

http://wiki.ross-tech.com/wiki/index.php/00470

Click to expand...

Wrong link

This is excellent information gents. Thank you SO much.

I'm beginning to suspect fraud on the part of the dealer, as when I called him back to find out upon what was the tech basing his diagnostic shift (to DPF). That was yesterday. The service sales dude dodged the answer with about 10 minutes of hold time, then saying "the tech went home, and he would call me today with the answer." No call today.

Tomorrow, I'll have the codes checked again. If there's no DPF code, I'm calling my AG's office. Either way though, I'm going to confront them on this TSB ignorance of their's and demad some recompense for this trial-and-error BS.

I cant seem to find any TSB, but I'll find ways.

TSB 01 14 21

# 2034898

google it, you should find what you need.

P0470,P0471,P0472 Exhaust Pressure Switch

Please refer to this part. It takes 15 min to replace. these are the error codes
P0470, P0471,P0472. The part costs 100.00 at dealer. Dealer wants 500.00 to replace.
Exhaust Pressure Sensor (Low Input).
VW part # 076-906-051-B replaces 03G-906-051G (which is a defective part). We need everything to call corporate and start requesting a recall to get our 100.00 back.

Another tip: so there are two sensors: one to the left of oil cap and one to the right (low sensor) VW now uses the same part for both places.