Passat TDI Starting Issues: 1Z Engine Troubleshooting

Hi.

It's about a car that belongs to a friend, but unfortunately, it's not located here with me.

Passat Variant 35i TDI with a 90hp 1Z engine from 1995, mileage >350,000 km.

The car starts briefly, revs up to just under 2500 RPM without any throttle input, and then immediately shuts off. The WFS (presumably a diagnostic system) shows no error codes, but the issue is flagged in the MSG (presumably a control module).

"Control unit defective" doesn't reappear after being cleared.

Where could we start here?

Best regards, Rüdi.

Was happened to the ESP? I remember that this could be a potential issue if the ESP is removed and not reinstalled exactly in the same position.

Unfortunately, I don't have a good idea either, aside from Kossmann's ESP theory.

The "MSG defekt" error doesn't quite fit with that. A side question: Was the reading done with a current VCDS version? Older versions from "other sources" sometimes provide error messages that don't match the error code .

If needed: I have a working ESP (Electronic Stability Program) module from an AHU engine (the 1Z successor) that I want to sell (my Golf has been sold a long time ago, so I want to get rid of the spare parts). If needed: Please send me a private message or email to my username at GMX.de.

Greetings.
Guste.