I have a 2001 S40 and the service light comes on when I start the car....but will go away app 2-3 mins later. Any idea's?

 

Means you need an oil change.
If you had one done recently then they didn't reset the light.

 

the service light wants resetting turn the ignition off hold the trip button in thats the one that resets the milometer whilst holding the button in switch the ignition on when the service light starts to flash release the trip button this is about 10 seconds that should reset it for you