Read Drive Away Assist Control Unit Directly?

Hello,

I want to install a new control unit in my Golf 3 TDI 1Z for an engine conversion. For this, I already went to a to have the control unit programmed to the keys. However, he told me, after presenting me with the bill, that he was unable to access the immobilizer control unit via software (the SG Airbag, etc. is working).
I suspect a cable problem. Is it possible to directly access the immobilizer control unit when it's removed? Would it be possible to temporarily install the immobilizer control unit into another Golf with working wiring to read the code?
I would like to keep the effort to a minimum.
Best regards and thank you in advance!
Jens.

Hello Jens,

What year is your 1Z? Models before 1994 didn't have WFS.

If your system has a WFS (Wing Fuel System), then there must be voltage supplied to the WFS, the reading coil must be functioning, and the K-line must be connected to the MSG (Main System Generator). Otherwise, the MSG would refuse to start.

Only the K-line connection remains between the WFS (Engine Control Unit) and the diagnostic connector. I would simply run an additional wire from the WFS to the diagnostic connector, in addition to the existing wiring.

If you want to find the error correctly, I would suggest checking the K-Line distributor. It's located above the fuse box. It's a long plastic block with several identical single-pin connectors (WFS, airbag, ABS, automatic climate control, automatic transmission, and a two-pin connector for the diagnostic port). In my G3, a connector had once come loose from there. Otherwise, you can easily access the WFS and diagnostic port from there for testing.

Regards,
Guste.

Hello Guste,

Thanks for the tip, I guess I'll have to check the wiring harness. So, if I understand you correctly, there's a direct connection from the immobilizer to the diagnostic box. Okay, great, that gives me a starting point.
Thank you and best regards.
Jens.