I did the recommended maintenance on my wife's 2007 S80 3.2 recently. Everything went well and I was able to reset the "book maintenance time" message with the tips from another forum. I'll add those tips at the end of this post.
I followed the Maintenance Service Operations tables on pages 60 through 65 0f the 2007 U.S.A/Canada Warranty and Service Records Information manual. To change the oil you must drop the plastic skid shield under the engine in order to access the oil pan drain plug. Be careful when replacing the seven mounting screws for the shield as they thread into plastic fixtures and can easily be stripped. The oil filter (on the passenger side of the engine bay near radiator) is not too difficult to remove if you dismount the power steering reservoir and hold it aside for clearance. To remove the oil filter cover I used a 36mm socket with a long extension.
Coolant level check is simple, just shine a bright flashlight thru the opaque plastic reservoir and observe the liquid level. If you jiggle the car you can see it slosh around in there. Battery water level check requires disconnecting the positive lead, which is simple and requires no complicated follow up. Just disconnect the black (neg) cable first, then the red (pos) hardware at the battery lead, check all 6 cells and add water as needed, reconnect the pos, then the neg cable and away you go. I plan on using an absorbant gas mat (AGM) battery when I do my first battery replacement. They are maintenance free.
Power steering fluid level check is easy. I filled the windshield washer reservoir and got about 4 ounces overflow onto the floor. Next time I'll stop short of full, based on the sound of the gurgle into the fill tube.
To access the cabin air filter door, I removed two torx head screws on the black cover that holds the light beneath the glove box. The cover drops down and you can unclip the light wiring connector to get the cover away from the passenger side foot well. You need to bend the carpeting down from the upper left corner, but the center console sidewall holds it in place, so pull the front lower edge of the sidewall and a couple snap-in fasteners will pop loose. Now you can move the carpet corner down and away from the area of cabin air housing, which sits directly in front of the center console. There are two compartments here and it looks like the aft compartment holds the A/C evaporator, or maybe the heater core, or both. Forward of this is a smaller compartment with a door on it. You can see the three "hinge" points on the aft edge and the three opening handles on the fore edge of this door. The upper handle is hard to see if you don't stand on your head and get way down in the foot well, but all three handles operate easily by the "Braille" method. Once the door is removed (it measures about 2 inches wide and 8 inches tall)you can tug on the filter element and it will slide out, bending as it goes. It is quite flexible with a felt frame around the filter pleats. Volvo Part Number 30767022 and BEHR part number K8741002. I ordered one on line for $29 plus shipping. My old filter element has a permanent distortion kink impressed on it and probably did NOT do a good job of keeping particles out of the cabin because it didn't fit the filter holder accurately. I'll be more careful putting in the new filter element than the last technician was. The new cabin air filter is a bit tricky to get in without kinks and bends. I removed the fuse block cover so the filter could be squeezed into the space between the firewall and glovebox. Then I started the process of push, pull, straighten and then more push, pull, straighten until I got the filter completely inside the housing. I feel very confident that there are no malformations in the new filter because i can easily slide it back and forth in the filter compartment. There are a few inches of clearance in which the filter can be withdrawn without having to bend and contort the shape.
The brake fluid min and max markings are inside the reservoir and visible after you remove the fill cap.
My front brake pads are like new and my rear pads are about 50% worn. I examined the pads by using a high powered flashlight and looking through the "spokes" of the mag wheels.
I have documented all my work in a log book and I can provide receipts to Volvo if I need to prove that the service was accomplished.
To reset the maintenance reminder message I followed advice of a mechanic from another forum and did the following:
Insert Key Fob.
Set Trip Odometer to T2.
(Foot off the Brake) press the Start/Stop button. This is Key Position I.
Press and hold the Trip Odometer reset button.
(Foot off the brake) Press and hold the Start/Stop button for 2-seconds (lights, et al come on). This is Key Position II.
When ( and as soon as it happens - you don't get much time here and it took me 5 tries) the Information symbol* flashes release the trip odometer reset button.
There may or may not be an audio confirmation.
The Maintenance Message will be gone.
Go to position 0 and on your next Start the message will have been cleared.
The Owners Manual Page 77 (Ignition modes) explains Position 0, I, II, & III
*The Information Symbol is the yellow light between the Speedo and the Tach.
The T2 Trip Odometer will be reset to Zero