2004 model 'regular service due' message reset - flunky
I took my car to be serviced 3 weeks before 1 year was up. Unfortunately now 1 year is actually up it appears the service counter was not reset, and when I start the car it says "regularly scheduled service due' on the LCD display.

Is it possible to reset this?
2004 model 'regular service due' message reset - Armitage Shanks {p}
Why not get the people who did the service but failed to do the reset to do it, or are they too far away? SFAIK the reset is part and parcel of the service you paid for.
2004 model 'regular service due' message reset - Dynamic Dave
The following is to reset an S40.

Not sure if it also does the S80?

www.servicereset.co.uk/phpBB2/viewtopic.php?t=10

You could always register an account and ask.