AFN Engine Problems: Common Issues & Solutions

Hello!
Here's the translation:

'This is about the following vehicle:'
Seat Ibiza GT TDI.
MKB: AFN engine with switchable chip (110/140 hp) from ******** (installed for approximately 45,000 km).

'Problem: The 'turbo boost' now kicks in around 2300 RPM, instead of the usual 1800 RPM. However, after that, it seems like all the power is available, and the maximum speed is reached. There's just a slight hesitation around 3500 RPM. Whether the 'chip' is installed or not, it doesn't make a difference. In the past, I experienced a complete loss of power. However, after cleaning the mass airflow sensor (Pierburg) with brake cleaner, everything was back to normal.'

So far, I have:
Have the error memory read: No entry .
LMM cleaned: Unsuccessful.
Visual inspection of hoses, connectors, etc.
The air and diesel filters are in good condition.
Does the AGR click when actuated externally, so it's working correctly, right?
Disconnecting the AGR (Abgasrückführung) system will not achieve anything.
VTG mechanism is operating smoothly (checked with a syringe).
And now?
Do you have any ideas?
Thank you in advance!

Rüttelplatte wrote:

The AGR clicks when actuated externally, so it's okay, right? Disconnecting the AGR does nothing.

Hi.

What exactly do you mean by AGR? The solenoid valve (which should click) or the diaphragm valve (if that clicks, it doesn't necessarily mean the valve is completely closed!)

As a precaution, disconnect the intake hose before the EGR valve and check the membrane valve's functionality by visually inspecting it and using a vacuum test.
The most important thing is whether it really seals completely (without creating a vacuum).
Possibly make it a little easier to operate.

The AGR clicks when operated externally, so it's okay, right?
Disconnecting the AGR will not achieve anything.

Hi.

What exactly do you mean by AGR? The solenoid valve (which should click) or the diaphragm valve (if that clicks, it doesn't necessarily mean the valve is completely closed!)

As a precaution, disconnect the intake hose before the EGR valve and check the membrane valve's functionality by visually inspecting it and using a vacuum test.
The most important thing is whether it really seals completely (without creating a vacuum).
Possibly, make it somewhat easier to operate.

I didn't check the solenoid valve. I manually actuated the diaphragm using a syringe, and it clicked. However, I don't know if the valve actually closed completely. Yesterday, I scheduled an appointment at the workshop for today to have a test drive with a diagnostic tool. And what happened? The problem suddenly disappeared on the way home! Today, I still had the error memory read: No entries. I wonder if some valve was stuck. Hopefully, it stays that way.