SOT -Negative spark advance, seeing this on my VW Tiguan Options

[fixer34]

Doesn't appear to be causing a problem, just never seen (looked?) it before. Had an OBD II scanner hooked up which also does real time monitoring. Was driving around and noticed that stopped/at idle, rpm was 750-800 and spark advance was -15 (15 ATDC?). Normal around town it runs about 2000rpm and +15, peaking to +20/25 at 3000.
Redline is about 5000, haven't pushed it near that.

Also noticed when backing off, even at 1500/2000, the advance will go negative.

Is this all part of the computer controlled emissions system?

[technicalninja]

Yes, normal operation, especially at idle.

The first variation of computer control on an ICE engine was idle alone.

Those late 70 early 80s cars were IMPOSSIBLE to set base timing on without putting them into "base mode". With GMs you crossed two terminals in the ALDL (check engine light) connector. Almost everything else had a "timing adjustment" connector somewhere.
Sometimes they were front and center in the engine compartment (like Toyota) and sometimes they were so hidden unless you knew exactly where to look you were screwed.
The OBD2 connectors made life SO much easier but by that time most adjustable timing distributors were gone so no more timing adjustments.

You'd set timing normally and pull the short. In computer control you might see 30 degrees either way and it would vary wildly. Most of the time you couldn't even see the timing mark. Looked like chaos!

Seeing something constantly stuck one direction was a cause for concern.

Unless you are also seeing DTCs in computer memory you have nothing to worry about.