Air Mass: Target vs. Actual Values in Block 3

Hello fellow mechanics,

I have a Golf III TDI/GTI with an AFN engine. Now that the target value table is available online, I used VAGcom to measure the values for my engine. I noticed that at idle, in block 0, field 10, the air mass is 140 (target: 69..135), and in block 3, field 2 and 3, there is a huge difference between the target and actual values. Target (field 2): 285, Actual (field 3): 480.

Since I've owned the car (4 months), the error code 0575, 'regulation difference,' has appeared occasionally. It usually happens when the engine is cold.

My question:
Does that indicate a defective mass airflow sensor?

Quote:

Does that indicate a defective mass airflow sensor?

Without further measurements, no. I would rather say that your AGR is...
defective.
The mass airflow sensor (MAF) value at idle is extremely unreliable for detecting a faulty MAF sensor. Ultimately, the MAF values are only relevant when the engine is running at full throttle.

Please search for "575" in the error databases and read the article about VTG adjustment.

@ Rainer
I'm experiencing the same issue with the excessively high values. You told me back then that it was likely due to a faulty AGR valve.
I've been racking my brains about it for nights, but I just couldn't make sense of it.
Could you please explain how you arrive at that?

Okay, here's the translation:

'Yes, it's true that my EGR valve is faulty due to a small metal plate stuck between the EGR valve and the intake manifold. How does the engine know that it's getting clean air? Aren't the values from block 3, field 2/3, coming from the mass airflow sensor (MAF)? Doesn't the MAF sensor only measure what's happening 'in front' of it?'

Sure, no problem.
David.

Quote:

The values from block 3, field 2/3, do they come from the LMM, right?

The LMM doesn't actually see what's happening "behind" it. }

That would be bad; it would mean that VAG would be installing a completely pointless part.

The LMM (Laminar Mass Meter) does exactly what its name suggests: it measures the mass of air passing through it per unit of time.

When the AGR valve is open, a portion of the intake air bypasses the mass airflow sensor (MAF) and is drawn in from the exhaust pipe. Consequently, a certain amount of exhaust gas continuously circulates within the engine. Therefore, for each unit of time or stroke, less fresh air is required.
When the AGR valve is closed, (almost) all the air is drawn in through the mass airflow sensor (MAF) and the air filter.

Best regards, Rainer.

Jo Rainer, thank you very much for your explanation!
I could have figured that out myself, but something was missing .
Best regards.
David.