This is usually caused by a faulty siren alarm module. Locking then unlocking the car with your keys will sometimes get the sunroof to close, but it may happen again if the alarm module is still bad.
One can replace the oxygen sensors in a Volvo S80 by them selves by utilizing the help of a Chiltons manual on Volvo S80s. The faster route though more expensive, would be to enlist the help of a certified Volvo mechanic.
The Volvo s40 is equiped with a smaller engine. The larger the number is next to the s, the bigger the engine and the faster the car goes. The three types of Volvos are: s40s, s60s, and s80s.