If not other symptoms are present, fixing the problem could wait, but may fail emissions test.
2=Moderate:Problem will more than likely fail the emissions test and may affect engine performance and/or gas mileage.
3=High:Problem requires immediately attention, may affect engine performance and/or reduce gas mileage, and could damage other components.
Repair may just require to clear the engine code, retight connector, fuel cap or check/top off fluids.
2=Moderate:Repair could require replacing a component (sensor, solenoid or switch) and clearing the engine code.
3=Hard:Expert repair recommended. Problem may require special tools and experienced technician to diagnose and repair.