S60 2001 check engine light with message.
 

Hi 2001 Volvo s60 first time Volvo owner. O have just over 100,000 miles . Today check engine light came on and message says emmissions system required maintenance. What are the possibilities or what does this message usually mean. Car also seems to be a bit sluggish possibly not shifting ( it's an automatic) at the right time. Also 2 times now I have got a message to pull over and check coolant reservoir. And it has been empty. I check all fluids everytime I get gas so never was even low and there is no obvious leaking of coolant or any other fluids. Help please.

first step is to have your car scanned for the DTCs (diagnostic trouble codes). Most big box parts stores (Autozone etc) will do this for free. Emmissions codes can be related to the catalytic converter (as measured by the oxygen sensors), can be the evap system (that recover fuel vapors back into the tank) etc. Given your car seems sluggish suggests you have a fuel trim issue, which can be caused by fuel metering (air intake leaks, exhaust leaks, engine temp sensor, O2 sensors etc), weak spark (plugs/coils) or fuel pressure (pressure sensor/regulator, pump, filter, injectors. DTCs will point you in the right direction. As to the loss of coolant - there has to be a leak somewhere as its a closed, pressurized system. Common causes are leaks around hoses, radiator seams, radiator core, overflow reservoir, heater core, heater core o-rings. You'd need to do a close inspection for any staining - it won't always be a puddle under the car. The worst case scenario is coolant is going into the engine because of a failed head gasket. First is to check the coolant for color and signs of oil in the coolant - then look for any foaming on the dipstick or filler cap (oil can get in the coolant, coolant can get in the oil...). A shop can do a pressure test on the radiator to help find a leak and test for HCs in the coolant (put there by exhaust gasses leaking out via the head gasket.