A6 2.0 TDI 16V DPF - Jerking/Hesitation at Constant Speed

I have an A6 that occasionally jerks or stutters while driving at a constant speed (around 1500-2200 RPM).
It's also very noticeable when starting the car; there's a strong jolt that makes the car literally "jump."
In addition to the extended acceleration phase, the preheating spiral is activated, resulting in the following error message:

008825 - Air leak in the intake system.
P2279 - 000 - - Warning light ON.
Freeze Frame:
Error status: 11110000
Error priority: 1.
Error frequency: 1.
Mileage: 173,494 km

I couldn't detect any leaks in the hoses, except that there are oil stains visible on the low-pressure cooler.

The car has also been chipped for approximately 40,000 kilometers.

Quote:

Furthermore, it's very noticeable when starting the car; there's such a strong jolt that you literally "bounce" around.

That could be something completely different, namely a rusted friction plate.
There's a technical problem report (TPI) regarding "corrosion of the clutch in humid weather," which can then lead to slippage when starting.

I sometimes notice that with mine as well. A good, thorough loosening usually fixes it for the day.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Yes.
Okay, thank you.
Da Du keine Frage stellst gehe ich mal davon aus, dass Du nun auch vor hast auszuschließen, dass die Ölspuren am LLK nichts mit dem Fehlereintrag und Undichtigkeiten in der LL-Strecke zu tun haben. Dann willst Du sicher mal den Abgasweg vor dem Hintergrund der möglicherweise schon seit längerem bestehenden Undichtigkeit in der LL-Strecke überprüfen. Sicher denkst Du dabei daran, dass eine LL-Strecken-Undichtigkeit zu hohem Rußeintrag in Ansaugstrecke und Abgasstrang führt und Bauteile dadurch schwergängig werden oder partiell verstopfen könnten. Und If you have done that, you will definitely want to post another report here, right?
haithamina

dieselmartin wrote:

Quote: Furthermore, it's very noticeable when starting the car; there's a significant jolt that makes the car "jump." That could be something completely different, namely a rusted friction plate. There's a technical problem report (TPI) regarding "corrosion of the clutch in humid weather," which can lead to slippage when starting. I sometimes notice that with mine as well. A good, thorough loosening usually fixes it for the day. m;

"It's not the clutch," he said, "because you can really feel it in first gear when it's already fully engaged."

haithamina wrote:

Yes, Okay, thank you. Da Du keine Frage stellst gehe ich mal davon aus, dass Du nun auch vor hast auszuschließen, dass die Ölspuren am LLK nichts mit dem Fehlereintrag und Undichtigkeiten in der LL-Strecke zu tun haben. Dann willst Du sicher mal den Abgasweg vor dem Hintergrund der möglicherweise schon seit längerem bestehenden Undichtigkeit in der LL-Strecke überprüfen. Sicher denkst Du dabei daran, dass eine LL-Strecken-Undichtigkeit zu hohem Rußeintrag in Ansaugstrecke und Abgasstrang führt und Bauteile dadurch schwergängig werden oder partiell verstopfen könnten. Und If you have done that, you will definitely want to post another report here, right? haithamina

I was hoping that someone else might have experienced a similar problem and could offer a solution.

I'm not entirely sure, but I believe that in this engine, the smoke reduction is achieved through control of the boost pressure rather than the mass airflow sensor (MAF).

"The pressure should be 2400 mbar for the low-pressure setting and 2100 mbar for the high-pressure setting, and it should also inject less fuel in the latter case."

Hello,

chli1976 wrote:

... I'm not entirely sure, but I believe that in this engine, the smoke reduction is achieved through control of the boost pressure rather than the mass airflow sensor (MAF). When using

, the pressure should be 2400 mBar, and when using LD, it should be 2100 mBar, and then it should also inject less fuel.
Does your model have both characteristic maps available? To check which one is active, simply look at measurement block 8. If the limitation based on air mass under load is "too high," it's being controlled by the Mass Air Flow sensor (MAF). Otherwise, if it's "too low," it's being controlled by the Manifold Absolute Pressure sensor (MAP).

When under load (meaning where the boost pressure should be relatively regulated, but there is a deficiency of 300 mbar), then there is inevitably air leakage in the intake system;-).

Quote:

You can easily access the turbocharger boost hose, specifically the section that runs from the turbocharger downwards to the intercooler, so check it there. Also, inspect the hose on the other side, connecting the intercooler to the intake manifold. Unfortunately, while the rubber is relatively stable, it has thin walls, which means that martens will inevitably chew their way through it. Of course, the fuel lines could also be damaged, but it's more likely that the hoses are the problem. Just look for oil residue on them. If you still have the original throttle control module (with EGR), it would also be necessary to check the tightness of the EGR valve and its actuation mechanism.

Here, the car vibrates so strongly that you literally "bounce" around.}
The engine mounts seem to deteriorate over time on this model; take a look at the rear one in particular, which is located near the transmission (you'll need to remove it, but the process is relatively straightforward). Also check the two front ones, one on each side.
By adjusting the support forward towards the locking plate, you can somewhat reduce the "wobbling problem," but not eliminate it completely.

Best regards, Rainer.

Yesterday I replaced the coolant reservoir, and I no longer seem to be getting that error message related to air leaks.
I am still waiting for a response from the owner.

I also updated the software and reduced the AGR (Automatic Gain Reduction) rate in the process. I haven't noticed any more stuttering, but I'm still waiting for feedback on this as well.

Hello,

Thank you for the feedback. Did the LLK develop a leak on its own (due to cracks, defective seals, etc.), or was it caused by external factors?

Best regards, Rainer.

No abrasions were detected; the external appearance was normal.