VW T4 Immobilizer Problem: Troubleshooting Guide

Hello.
I'm new here and hope I've posted my question in the correct category.

Okay, my problem is that I bought a VW T4 2.5 TDI with 102 horsepower.
Unfortunately, the first major problem occurred upon delivery: it starts briefly and then shuts off again.
I suspected it was the immobilizer, which was confirmed to me by VW when I had the car towed there. They tried to reprogram the key, somehow online or something, but I don't know anything about that. However, it didn't work. They told me that the key wasn't communicating with the decoder or that the control unit wasn't being unlocked.
Okay, so my question is, is there any way to bypass the immobilizer, or can I troubleshoot the problem without having to spend 1200 euros?
Thank you for any feedback.

How is it possible that you bought a car with a blocked WFS (Vehicle and Traffic Information System)? The seller should have taken care of that! Or is the car stolen?

"This is not stolen; it's from an insolvency case, and I believe the key is not original."

First, the cable connection of the reading head needs to be checked.

If the WFS control unit is defective, I would install a used one.
The price is around 50 euros.

What is the year of manufacture of the car?

Hello.
The connection is okay.
I already had the vehicle checked at VW, and they said that the main control unit is not being unlocked. How does that actually work? Does the reading coil read the transponder values and pass them on to the immobilizer control unit, which then unlocks the main control unit? Is that correct?
Is the immobilizer control unit compatible, or does it have to be the exact same model? Is the control unit a separate unit, or is it integrated somewhere?
Can this perhaps be circumvented?
Oh man, it's 2000.
Best regards,

The WFS control unit is located separately in the T4, to the right behind the speedometer.
It's possible that this part could also have been installed in a Golf 4 Cabrio, but I'm not sure if it would be compatible.

You won't find any tips here on how to bypass the WFS.

I meant compatible in the sense that if I were to purchase a WFS control unit and the corresponding key transponder, would they work together, or do they need to be compatible with the main control unit?

You only need the WFS control unit.
Then you still need to train it.
It can only be done with VAGCOM, but you won't have the login code for it.

Either you find someone who can read the login code for you, or you go to a VW workshop.

What is the year of manufacture of the car? Are there transponders in the keys? } Are these the keys to the car? }

Year of manufacture: 2000. I don't know if the transponders in the receiver are original.

Is your problem already solved?