AU Failure: Replace PD Element?

Hello professionals,

I have the following problem:

My Golf unfortunately failed the emissions test (AU) during its first vehicle inspection (HU) in recent weeks. The reason was the poor k-value (soot content).

I drive a:
Volkswagen Golf IV, 1.9 PD TDI, 74 kW, manufactured in 09/2001, 75,000 km, no chip tuning or similar modifications.

I drive approximately 100 km daily on country roads and highways. I only refuel with Esso normal diesel. The oil consumption is about 0.25 liters per 1000 km.

Blue/white exhaust smoke during cold start. Uneven idling and slight jerking when warm. Slight 'stuttering' or 'acceleration hesitation' at low speeds and when driving at low RPMs.

Due to the failed inspection, I contacted my Bosch service advisor. The initial suspicion was a faulty PD element.
'The engine was run to clear any issues,' but it didn't achieve any success. Unfortunately, my Bosch service center lacked the appropriate measuring instruments to perform a fault analysis. That is, my Bosch service center took the car to a trusted mechanic.

A short time later, I received a phone call with the information: 1 defective PD element. The cost for the replacement (only the defective one) is 603.00 euros, including installation.

The request for goodwill was made by the customer, but was immediately rejected, even though my car is still within the 3-year warranty period.

I have read a lot about PD elements in this forum, but I haven't found a comparable case.

I read here that you always have to replace all 4 elements at the same time. And what's the deal with this software update?

Ich hoffe, hier kann mir jemand helfen und etwas Mut machen. Könnte es noch eine andere Ursachen haben bzw. muss wirklich das PD-Element getauscht werden oder ist es reine Abzocke? So fährt mein Golf tadellos. Und das Ruckeln und die Abgaswolke scheint ja normal bei einem PD zu sein. Ohe?

Thank you for your help, and have a safe journey!

Best regards,
Danny.

Hi Danny,

FMO#82 wrote:

And what is this about the software update?

You can read more about it here:
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
Unfortunately, you can only determine if your car is included by checking the STG number.
However, given the year of manufacture you mentioned, your engine might also be an ATD model. That model is not affected by this issue.
Please post your engine code.

Quote:

Und das Ruckeln und die Abgaswolke scheint ja normal zu sein. Or what?

Neither the ATD nor the AXR showed any noticeable fluctuations.
The AXR typically doesn't produce any visible black smoke.
He should easily achieve a turbidity value of 2.0.

Neither the ATD nor the AXR exhibited any noticeable flickering.
The AXR typically doesn't produce any visible black smoke.
He should easily achieve a turbidity value of 2.0.

Unless there's a leak somewhere in the charging air duct or the AGR (Abgasrückführung - exhaust gas recirculation) system isn't sealing properly...

Neither the ATD nor the AXR exhibited any noticeable flickering.
The AXR typically doesn't produce any visible black smoke.
He should easily achieve a turbidity value of 2.0.

unless the intake air path has some kind of leak, or the EGR valve isn't sealing properly......
Hello Bertil and joegs,


I can't post the engine code right now because my car and registration are with the dealer.

Assuming I have an ADT engine, will replacing it with a new engine control unit (part number 038 906 019 MQ) transform it into an AXR engine, and will that solve all my problems (such as excessive soot and idling issues)?

Then, exchanging the PD element would indeed be a rip-off. But why did the dealership show a defective PD element? Or was it just a fake from the dealership to make money?

FMO#82 wrote:

... will then be converted into an AXR model using a new control unit (part number 038 906 019 MQ), and all my problems (soot and idling issues) will be resolved...?

... Keep dreaming. ..... The AXR is fundamentally different from the ATD (search function). Apart from the block and the same performance, these two engines have little in common.
Replacing the catalytic converter has absolutely no effect on soot emissions! Don't read into things that aren't explicitly stated!


Regarding soot, I would first check for a lack of boost pressure (e.g., a leak in the boost pressure line, a stuck VTG, a faulty mass airflow sensor...). Also, your description about the acceleration holes suggests a leak in the charge air system.

A defective PD element, which is diagnosed as faulty, should hardly function at all. The engine would likely run very unevenly.
While a deviation in the idle speed control might suggest a failing pressure differential (PD) element, it's unclear whether this is sufficient to cause such excessive soot buildup.

The ATD doesn't stutter or jerk. And the Russ is also well-behaved. Only under the spotlight of Hintermann's actions is there something to see.

Okay, I picked up the car from the dealer yesterday evening.

A PD component was replaced, and a new AU (general inspection) was performed. The total cost was 720.00 €. The soot values are now all within the acceptable range, and the AU was passed.

From a feeling perspective, the car runs much smoother and more consistently in the lower RPM range. The jerking or shaking at idle is no longer an issue, whether the engine is cold or warm.

No differences compared to before are noticeable in the higher RPM range.

Regards, Danny.

Hi Danny,

FMO#82 wrote:

.... A PD component was replaced.... Soot values are now all within the acceptable range, and the AU test was passed.

Thanks for the feedback... I would have bet that it wasn't a defective PD element. Well, you never stop learning.

@ FMO#82:
And VW doesn't want to contribute to the costs? Or were you able to achieve something after all?

Hello delvos,

Unfortunately, not. The request for leniency was submitted by a friendly person, but it was immediately rejected. A second attempt also yielded nothing. I am stuck with the costs.

Or does anyone have an idea or suggestion on whether I can contact VW directly?

I'm still annoyed, but at least the car is running well again. By the way, the PD element is (still) not an officially recognized wear part. A few years ago, VW would certainly have been willing to take over the cost. Unfortunately, that's not possible anymore these days. It's actually outrageous, but what can you do.

Do you think I should try contacting VW directly? Is there a specific department I can reach out to? You're right, I shouldn't just let this go.

@Bertil
Who knows, maybe the PD element wasn't even replaced...? You can do that with unsuspecting customers... (This is not an accusation ).

Hello!

You definitely have to try contacting VW directly again!
You can inquire about the address by calling the 0800-VOLKSWAGEN hotline.

You need to contact a specific department (Department V...?) directly in Wolfsburg. Explain your problem to them politely but firmly, and emphasize that it's incomprehensible to you why a part that should last the entire lifespan of a car, especially in a relatively new and low-mileage diesel, has already broken.

Best regards,

FMO#82 wrote:

... Oil consumption is approximately 0.25 liters per 1000 kilometers. ...

I find it a bit too much, somehow.

...
Oil consumption is approximately 0.25 liters per 1000 kilometers.
...



I find it a bit too much, somehow.
I also! But it's still within the tolerance range. I definitely don't make it the 30,000 KM between each inspection without needing to top up the oil. Why do I even need LL (But that's another topic).

It is a specific department (department V...?!), which must be contacted directly in Wolfsburg. You should then explain your problem to them in a friendly but firm manner, and point out that it is incomprehensible to you why a relatively new and low-mileage car (for a diesel) would have such a part, which is supposed to last for the entire life of the car, already broken.

Hi,

I'll give them a call. I'll also keep you updated.

'Thank you!'

Best regards,

Now it's my turn to chime in:

FMO#82 wrote:

A request for leniency was submitted by the customer, but was immediately rejected, even though my car is still within the 3-year warranty period.

What exactly is meant by "guarantee" here?

If that were an extended warranty , I wouldn't understand the world anymore...