Volvo: S-80 vOLVO cruise control, electronic throttle control, vacuum lines

Question
QUESTION: I have a 2001 S-80, 2.9, non turbo, with two issues:  just changed oil--how to reset service light (stays on for approx 2 min. every start up) and just replaced MAF-code gone-but still have a  500 rmp idle surge--no code showing--good vacuum at manifold and no leaks with brake fluid spray.  Please help with a least service lite.
ANSWER: Joe,
Key in Position #1 hold in the trip reset button then turn the key to position #2 continue to hold in button until the service light begins to flash, release the button, light is now reset.
For the idle have the adaption reset. If that will not solve the idle issue you may need the Electronic Throttle Control checked and new software installed. These two procedures will require a Volvo scan tool.

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QUESTION: What's the most common, easy fix for a non-functioning cruise control on a normally aspirated 2001 s-80 Volvo?

Thank you

Answer
Joe,
Most times the vacuum hoses to the diaphragm are at fault. The switches on the brake pedal also have a vacuum line and also sometimes go out of adjustment. When the vacuum lines are good test the switch to see if it holds vacuum until the pedal is depressed.