Malfunction Indicator Lamp: Description and Operation
Malfunction Indicator Lamp (MIL)
If the lamp comes on (or stays on after the vehicle has started), the engine diagnostic system has detected a possible fault in the emission control system. Although driveability may not he affected, see an authorized Volvo retailer as soon as possible for inspection.
NOTE: If the fuel filler cap is not closed tightly or if the engine is running when the car is refueled, the Malfunction Indicator Lamp may indicate a fault. However, your vehicle's performance will not be affected. Use only Volvo original or approved fuel filler caps.