THE ENGINE MANAGEMENT LIGHT on my volvo S80 COMES ON OCCASIONALY AND SAYS THAT THE CAR NEEDS AN ALARM SERVICE BUT DOES NOT DETRACT FROM THE DRIVE OF THE CAR

The check engine light comes only when the computer control unit (called the PCM) senses a fault in the electronic controls of the engine and/or the emission system, there are about 200 possible faults that turn the light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen and Autozone parts stores do this testing for free. The check engine light comes only when the computer control unit (called the PCM) senses a fault in the electronic controls of the engine and/or the emission system, there are about 200 possible faults that turn the light on, to know what has developed a problem you must have the system tested, this is called an OBD2 fault code test, Kragen and Autozone parts stores do this testing for free.