Immobilizer Coding Lost: Engine Control Unit Problem

Hello everyone,

Okay, I'm having another small problem with an AFN engine control unit (ECU) from a Golf Mk3. It's the 028906021DF part. It pairs perfectly with an immobilizer control unit (1H0953257B) and then runs great. However, the moment you turn off the ignition, the coding is lost again. I tried clearing the adaptation values in the engine control unit (in addition to the adaptation values of the immobilizer). Then I could start the engine three times. Then the same thing happened again: it runs for 1 second and then stops.

Does anyone of you know anything about that?

Best regards, Max.

If the problem disappears after turning off the ignition, then your learning process was never successful, and you only had the emergency start function activated.

Could you please post a diagnostic log and tell us which version of VAG-COM you are using?

Lernwerte im MSTG löschen? Huh?
The 021DF does not have any learnable values that can be deleted.
If something goes wrong, it's likely happening within the WFS STG.

Hello,

Okay, as I said, it started a maximum of three times. You can also save channel 00 in the engine control unit; according to VAG-Com, this resets the learned values. I can't say whether anything happened there.

"The learning process for the WFS works perfectly with a different control unit. I am using the latest VAG-Com version along with a USB adapter. I need to check some details on my laptop. Besides the error message 'Engine control unit locked,' there are no other errors stored, neither in the MSG nor in the WFS."

To be honest, I don't think it's the emergency start function, because after turning off the ignition, it works once, but it records three times...

Best regards, Max.

Hello,

Okay, as I said, it took a maximum of three attempts to start. You can also save channel 00 in the engine control unit, which, according to VAG-Com, resets the learned values. I can't say whether anything happened there.
Nothing happens with the TDI (at least with the STG generation).
With a different control unit, the learning process for the WFS works perfectly.
The pairing process can only be performed within the WFS STG system.
Could it be that the WFS already knows the other MSTG because it was originally...?
is installed in the vehicle?
Have you ever adjusted the learning parameters in the WFS STG?

Hello,

Yes, the pairing process has always been done within the WFS-SG system.

Okay, here's a brief summary of everything:

So, the original engine control unit (ECU) was removed (part number 028 906 021 JJ) due to problems with the cruise control and because it simply couldn't be programmed for a manual transmission, even though it was brand new.

Then, for testing purposes, I entered 028 906 021 DF. The adaptation process went relatively smoothly. Ignition off, laptop disconnected. It starts... I drove it out of the hall, parked it... it wouldn't restart, or only for 1 second. So, I took the laptop out again, and deleted the adaptation values in the WFS-SG... ignition off... it runs again, just once. Then, for testing purposes, I saved channel 00 in both the WFS and the MSG. I was already happy because it starts perfectly on the third attempt. Five minutes later, on the 4th attempt, it didn't work again .

Okay, so I'm putting the original part back in (which, by the way, isn't related to the engine or the WFS-SG system), and that works... I'm starting to think the DF unit is faulty. I'll try it on another TDI soon, and see what happens...

Best regards, Max.

Hello Max,
Now, some things are clearer .
I'm concerned that something might be wrong with the electrical system in your car (T3 conversion?).
is in a state of disrepair.
If you have the opportunity, build an adapter that allows you to connect to the engine control units.
you can operate directly on your desk.
ECU:
Pin 1: Ground.
Pin 23: 12V.
Pin 61: K-Line.
Diag:
Pin 4,5: Ground.
Pin 16: 12V.
Pin 7: K-Line.

'The K-Line needs to be directly connected. Both connectors require 12V and ground connections, and there needs to be an input for a power supply (12V / 1A is sufficient; the MSA15 draws more power).'
approximately 300mA when it's running).

Then you should be able to code that as 00002 as well!

Best regards,
Rudi

Hi there,

if I connect the K-line directly to the diagnostic connector, then I'm probably out of luck and can forget about the possibility of flashing it .

I've built a similar connector before, but with the option to also connect the WFS.

I haven't connected the SG 021 DF to the connector yet, but I'll do that soon.

I'll get back to you later. However, I'm starting to think there might be something wrong with it.

Best regards, Max.

You should not connect anything in the car.
It's about running the bare MSTG (Motor Steuergerät) directly on the VAG-COM interface connected to a PC.
without interference from the vehicle's wiring.

Best regards,
Rudi