Emission Control Systems: Description and Operation: Overview

Engine Emission Control

OVERVIEW
The engine emission control system on the 4.2L engines (Supercharged and NA) comprise:
- Crankcase ventilation system
- AIR (secondary air injection) system
The crankcase ventilation system consists of two hoses, connected between the left-hand valve cover and the intake manifold and the right-hand valve cover and the air cleaner outlet pipe and a PCV (positive crankcase ventilation) valve located on the top on the LH (left-hand) engine cam cover. The PCV (positive crankcase ventilation) system recycles crankcase gases back through the engine where they mix with incoming air/fuel charge and help to reduce hydrocarbon emissions.
The AIR (secondary air injection) system comprises the following components:
- AIR (secondary air injection) pump
- AIR (secondary air injection) switching valve
- AIR (secondary air injection) control valve
- AIR (secondary air injection) vacuum reservoir
- AIR (secondary air injection) pump relay
- AIR (secondary air injection) pressure sensor (North American specification vehicles only)