Volvo S60 - Manual (Page 258)

06 During your trip
Refueling
06
258
Heated oxygen sensors
The heated oxygen sensors monitor the oxy-
gen content of the exhaust gases. Readings
are fed into a control module that continuously
monitors engine functions and controls fuel
injection. The ratio of fuel to air into the engine
is continuously adjusted for efficient combus-
tion to help reduce harmful emissions.