TDI AFN: Emergency Mode & Error Codes

On Saturday, I drove about 300 km, and I experienced the emergency mode three times during the trip. The first time was when I was transitioning from one highway to another. On the first highway, I drove at full speed for about 70 km.

The second time it happened, I was going at around 200 km/h, then I let off the gas and accelerated again to 170 km/h.

Das ditte Mal war auf der Landstraße, als nach einem Überholvorgang im 4. Gabbreviations

During the first test run, I happened to be monitoring the LDA (Lambda-regulated direct injection). The boost pressure, which was 0.8 bar at full throttle in my case, increased to 1.5 bar when accelerating, and then dropped to 0.1 bar after the typical jerk associated with the test run.

After each restart of the car, the error message would disappear. At home, I connected my laptop and OBD cable, and as often happens, I got the error code 00575 (difference between intake manifold pressure control and actual pressure), and additionally, for the first time, I got the error code 00519 (intake manifold pressure sensor - short circuit to positive). I've cleared both error codes for now, but I won't drive the car again until tomorrow! The mass airflow sensor (MAF) and pressure sensor have already been replaced because I've seen the intake manifold pressure control difference error before. The intake manifold pressure sensor error is new.

Could all of this be related to a stuck VTG (vaneless turbocharger), or is the sensor in the control unit (ECU) defective? Is it possible to make the VTG functional again without removing it?

Regarding the vehicle: Volkswagen Golf 3 TDI, engine code AFN, first registration 11/1997, mileage 245,000 km.

I can't help you with your fault memory issue, but if you're having trouble with the VTG system itself, you might want to take a look at this.

I am unable to access external websites or specific files online, including the URL you provided. Therefore, I cannot translate the text from the German link.

Regards,
Uli.

marcel.d wrote:

... for the first time 00519 intake manifold pressure sensor - short circuit to positive.

Ouch
If it keeps coming back despite treatment, you probably need a new MSTG.
Nonsensical errors are not caused by the infamous relay 109.
Depending on your skill level, you should either repair the connection, resolder it, or replace the component.

Best regards, Micha.

Wiesel wrote:

marcel.d wrote: ... for the first time 00519 intake manifold pressure sensor - short circuit to positive. Ouch If it comes back intentionally, you probably need a new MSTG.

Are you sure? Wouldn't this error also be triggered if a charging pressure above the measurement range is applied to the sensor for a defined period of time?

That would fit with his observation on the analog LDA of >1.5 bar relative pressure.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.

That's right.
The error occurs after approximately 2.5 seconds of continuous streaming.
In that case, "gezielt" could be misunderstood .
" 'Under normal driving conditions' would have been a better phrasing."

Best regards, Micha.

Okay, in the workshop today, the VTG (Variable Turbine Geometry) was made functional. Unfortunately, the "STG (Steuergerät - control unit) defective" error still occurs as soon as you give it full throttle. It looks like a new control unit will be necessary. I've already found some, also from a Golf 3 with the AFN engine. The part number is the same except for the last letter. Does that last letter also need to match?

Yes, the letter is part of the part number, so it should be correct.
What does "einmal Vollgas" mean for you?
As previously mentioned, the pressure exceeding 1.5 bar needs to be maintained for more than 2.5 seconds to trigger the error.
Are you still seeing 1.5 bar on the boost pressure gauge?
Longer than 2.5 seconds?

Best regards, Micha.

No, the LDA (Lambda-Sonde) now reads a maximum of 1.1 when running on Overboost, and 0.8 at normal full throttle. Regarding the engine control units (ECUs), I've read that the letters indicate something about the starting fuel injection volume. I haven't found any ECUs with the ending letters "GH" yet...

marcel.d wrote:

No, the LDA now goes up to a maximum of 1.1 with Overboost, and at normal continuous full throttle, it's at 0.8.

That already looks pretty good.

Quote:

Regarding the control units, I read that the letters have something to do with the starting injection amount.

That's - if I may say so - complete nonsense.
With 028 906 021 xy, you cover all possible TDI engines with 66 and 81 [presumably referring to engine codes or sizes].
kW values in various Audi, VW, Skoda, and Seat models, with differences existing even between (sometimes equally powerful) models.
Differences in the wiring of the input connections exist between Audi and VW.

Quote:

I haven't found any yet that end with the letters GH...

I have a spare 021GG PROM module for my Golf, which has socketed PROMs. It's also compatible with the 021GH. How much are you willing to spend?

Best regards, Micha.