Volvo: 2001 v70 xc cross country PO333 code, fuel milage, service reminder

Question
Hi, I have a check engine light, PO333 knock sensor circuit high imput. Car seems to be preforming fine, no decrease in fuel milage. What is the knock sensor? Also is there a reset procedure for the service reminder light? Thanks, Marcus

Answer
Marcus,
Put key in position one push the trip reset bitton holding the buttom turn the key to position two until the service light flashes, release the button, it is reset.
Knock sensor hears a knock from poor gas and retards the spark until that knock stops. Clear the code and drive the car if the code cotinues to come back get the Volvo scan tool to read the codes as that tool will be more specific as to the fault reasons.