The "service engine" light in the Volvo S60 serves an important purpose. This light alerts you to problems with the car's exhaust system or malfunctions of the mass air flow sensor. Its most common use, though, is to alert you that the car is in need of an oil change. Many S60 owners choose to do the oil change themselves, as the procedure is very simple, but they do not possess the sophisticated electronics to reset the car's computer to shut off the indicator light. For these owners, there is a way to turn off the light manually.
Place the key into the S60's ignition.
Press down on the S60's odometer trip reset button and hold it there.
Turn the key to the "II" (accessories) position in the ignition.
Continue to hold the odometer trip reset button until the Service Engine Light begins flashing.
Release the odometer trip reset button and turn off the key in the ignition. Your service engine light should be reset to off. If it turns on again soon, your S60 might need service.