Service Engine Soon Light

[NW1]

I understand the distinction between a "Check Engine" light and a service reminder. SES is not so clear to me.

Trying to reset the SES ('08 3.0si Roadster) but to no avail following this procedure (I have a US car) https://www.youtube.com/watch?v=DfHlP5mEQkk&t=55s

Does a P code (Pxxxx) force the SES or is there some other indication?

Thanks!