System Description
The Differential Pressure Feedback EGR system controls oxides of nitrogen (NOx) emissions. Small amounts of exhaust gases are recirculated back into the combustion chamber to be reburned with the air/fuel charge. The EGR system consists of a differential pressure feedback EGR sensor, EGR valve, EGR vacuum regulator solenoid, EGR orifice tube assembly, related wiring, PCM and vacuum hoses. (Scheme 1)
Scheme 1
The Evaporative Emission (EVAP) system prevents fuel vapor build-up in the fuel tank. Fuel vapor trapped in fuel tank is vented through the vapor valve assembly on top of fuel tank. Fuel vapors leave the valve assembly through a single vapor line and continue on to the EVAP canister for storage until vapors are purged into the engine for burning. EVAP canister is located in engine compartment, in rear of vehicle near luggage compartment or underneath vehicle along the frame rail. There are 2 different types of EVAP systems that may be used
- Enhanced Evaporative Emission (EVAP) System
- On-Board Refueling Vapor Recovery (ORVR) Evaporative Emission (EVAP) System