I have a1998 Altima. The service engine light came on. Had it diagnosed and received error codes P0440 and P1448. What are these and are they easy to fix?

The P0440 code indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. The P1448 code indicates that the EVAP Canister Vent Control Valve is open. The EVAP canister vent control valve is located on the EVAP canister and is used to seal the canister vent. This solenoid valve responds to signals from the ECM. When the ECM sends an ON signal, the coil in the solenoid valve is energized. A plunger will then move to seal the canister vent. The ability to seal the vent is necessary for the on board diagnosis of other evaporative emission control system components. This solenoid valve is used only for diagnosis, and usually remains opened. When the vent is closed, under normal purge conditions, the evaporative emission control system is depressurized and allows EVAP Control System (Small Leak)diagnosis

Good call on both the codes. I've seen P0440 a fair amount...a very general code something is wrong in the emission system. And I think the last time my '01 Frontier threw a service engine code it was for an open vent or valve somewhere in the emission system (not the engine). I think it might have been on the charcoal canister. I've heard on some Nissans, vents in the emissions system will stick open sometimes. That's what happened on mine. I reset the code (for what it's worth, I also unscrewed and re-tightened the gas cap) and drove it a while. The light has never come back on. If these are the only two codes, I don't think it would hurt to have someone reset them for you and drive it a while to see if they come back on (it's likely they're both for the same issue). If it doesn't you're fine. If it does, you'll have to replace something in the emission system (not certain what, though prob not the expensive catalytic converter). But it you want to reset the code and run the vehicle, it shouldn't hurt anything.