Heated oxygen sensors

The heated oxygen sensors monitor the oxygen 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 combustion to help reduce harmful emissions.
See also:
Symbols in the main instrument panel
Indicator and warning symbols
Other information symbols
Information symbols in the center
console display
Information symbols in the ceiling
console
...
Unleaded fuel
Each Volvo has a three-way catalytic converter
and must use only unleaded gasoline. U.S. and
Canadian regulations require that pumps delivering
unleaded gasoline be labeled "UNLEADED". ...
