Vauxhall Insignia u0100, u0140 faults

Hey everyone,

I've got a persistent issue on my 2011 Saab 9-5 New Generation (NG), A20DTH 2.0 diesel (SAME ENGINE AS THE INSIGNIA).

Symptoms (constant, no reset on unplugging the battery):

Idle is stable at ~1000-1400 RPM.

When pressing the accelerator a bit more (even in neutral), revs climb but immediately start hunting/dancing between 1600-1800 RPM.

After ~15 seconds of holding throttle, the engine completely shuts off.

No check engine light, no codes on generic OBD2 scanner (engine ECU only).

Light driving is somewhat possible at low throttle, but any real acceleration triggers the rev hunting and eventual cutoff.

Anyone with a 2010-2012 Saab 9-5 NG diesel had this exact issue? Or similar on Opel/Vauxhall Insignia A20DTH?