Audi A1 P0299: 1.4 TDI CUSB Error Code Fix

Hello everyone,

My Audi A1 1.4 TDI with engine code CUSB went into limp mode on the highway due to this error (P0299) and lost all power.

In the meantime, the air filter housing and pressure hoses were inspected, and a suspicious-looking pressure hose was replaced.

Over the weekend, the magnetic valves and turbocharger pressure sensors were replaced, and the vacuum hoses were checked – everything was as it should be.

The car has no power, and the pressure sensor on the turbocharger is working, but the boost pressure changes to a vacuum when accelerating from idle.

Sure, here is the translation of the text from German to English:

"LG" can be translated as "Best regards" or "Sincerely". It is a common abbreviation for "Liebe Grüße", which means "Warm greetings" in English.

Welcome to the forum.

"In general, we prefer the complete diagnostic trouble code (DTC) report (Autoscan) because it sometimes contains additional information beyond the actual error code itself. We also appreciate a log file that captures the error event. This often provides more details than a written summary."

You're talking about vacuum instead of boost pressure. First, you should check if the turbocharger is still functioning correctly (check if it spins freely and has minimal play). Also, take a look at the air filter and see what else could be causing a vacuum. Finally, where are you measuring the boost pressure? Before or after the throttle valve?

Regards,
Sure. Here is the translation of the text from German to English:

"Guste" translates to "gust" in English.

Hello and thank you for the reply.

I think we don't need the scan anymore...

Images of the compressor taken with an endoscope.

Oh. I'm sorry to say that my fears were justified.

Now it's important to not only look for a new charger, but also to check if the motor has survived any residual charge from the old one.
If applicable: Thoroughly verschandeln all charge air pipes, intake manifold, etc. The intercooler is difficult to clean. It's better to replace it before the engine ingests any more parts.

PS: Aside from the emergency stop, did everything else seem normal? I would have expected more of a spectacle if the loader had broken down on the highway.

My condolences. Additional tip: After the repair, check if the intake manifolds or the turbocharger system are airtight, so that the new turbocharger doesn't get permanently over-revved due to leaks and break down again.

"What's surprising is that I replaced the hose with a pipe between the throttle body and the intake manifold, and I didn't notice any metal parts. However, what I did notice was the amount of oil in the intercooler and on the throttle body, which seemed like too much for my taste. According to the mechanic, it's normal."

Today, I used a lung exerciser because it's the only thing I have to try and clear my airways. There are no metal parts on the other end, and it seems to be completely open. I checked with my fingers to see if I could feel anything blocking it.

The aggregate carrier is a problem that's keeping me busy; let's see how I can fix it. It's also an issue with the A4, well, it's just an Audi thing.

And Turbo, well, there are plenty of special offers available for trades. I don't know if it's possible to repair the turbocharger like Turbobauer does.

Let's see, first things first, that one needs to be removed.

No prior warning. Emergency mode: no power, no sound.

I'm currently reassembling something again.

New LLK (likely referring to a lubricant or coolant) needed because the chips are full.
Ladeluftstrecke gereinigt incl. Ansaugbrücke. Da war nichts. No chips.
The AGR track was cleaned, and there was nothing but soot present.
AGR Kühler, da war die Turbowelle auf der Klappe. Nothing else.
Supply line, return line, new.
Turbo repaired by Turbobauer in Neckarsulm (regarding oil supply).
The DPF has been cleaned; it was completely full. (It was probably the cause of the problem.)
Ölwanne unten Ab, Sieb sauber. Verkokung hält sich in Grenzen. Gcleaned.

"How can I crank the engine with the starter without the diesel motor actually starting? That way, at least some oil would circulate before the turbo kicks in."

Unfortunately, the topic ended up in the wrong forum .

Quote:

Turbo repaired by Turbobauer Neckarsulm

. Were the

Quote:

plain bearings also replaced?

Quote:

The DPF has been cleaned; it was completely full.

The turbocharger is unlikely to fail due to this; it's more likely to be caused by poor lubrication, over-revving, or material defects.
}Question: How can I rotate the engine with the starter without starting the diesel engine? Then, at least some oil would circulate before the turbo kicks in.} Fill the connection port of the oil pre-supply line with motor oil. After the first start, let it idle for at least one minute.
hg
Herbert.

"Were the plain bearings also replaced?"
Middle section, new compressor housing, new.

"Fill the oil inlet port with engine oil. After the initial start, let the engine idle for at least one minute."

Is it done? Is that enough? My colleagues just suggested using the starter motor to crank it so that oil gets everywhere again.

"The TL (turbocharger) is unlikely to break due to its design; instead, it's more likely to fail due to inadequate lubrication, over-revving, or material defects."

Okay, the inlet and outlet were clear, as well as the oil filter screen. There was some carbon buildup in the lower part of the engine. I'm not sure what the cause was. The turbocharger and shaft are similar to those found in the Polo 1.4 TDI Diesel forum...

Why does it have two differential pressure sensors, each with only one hose connected to it?

That's enough after the initial inspection (RLF). If you absolutely must, then proceed as you would with a compression pressure test.
The EA288 engine has a differential pressure sensor and a pressure sensor for the low-pressure EGR system due to EU6 regulations. More details can be found in the relevant Technical Service Bulletin (SSP).
hg
Herbert.

PS: Moved the topic to the diesel forum.

Reset the particle filter learning values with VCDS and register the new differential pressure sensor. Where can I find this in VCDS?

Thank you.

Quote:

DPF cleaned, it was completely full.

How was it cleaned?

If you're interested in understanding what's happening and what it's about:
Diesel particulate filter, its cleaning and function

Good morning.

It was cleaned at AutoDPF. I can't say exactly how they did it, because they use different methods depending on the condition of the part, or sometimes combine different methods.

Attached is the report, and the differential pressure sensor that was attached to the contaminated pipe has also been replaced.

Hooray, it looks like an action that is actually useful (unlike dumping chemicals into the DPF).

Applying the new ash material, see my linked article for details.

The differential pressure sensor does not necessarily need to be reset unless it has been replaced; otherwise, there is no point in doing so.

If the "zero point" of the differential pressure sensor is off (ignition on, engine off, and a differential pressure greater than a few millibars is measured), follow a similar procedure and simply check the entries.

Calibrate differential pressure sensor

The differential pressure sensor was replaced because the line was full of soot. There is no adjustment procedure as described in the manual.

Adaptation is then done via the dropdown menu, but there is no entry available here.
I used the method with intervals of 5 seconds and 40 seconds.
Hopefully, it understood that.

In the same channel, there is a function to reset the particulate filter ash mass.
"Which is what I did. Value: 0 because it was cleaned exceptionally well."

It also has a feature for venting the cooling water. It was set to "active," but no confirmation message appeared after 10 minutes.

What is the purpose of turbocharger adaptation?

The motor runs very quietly.