The working principle of EGR system is to return the exhaust gas to the engine. Quantity of oxygen will be reduced with the intake air blended with the exhaust gas, resulting in a lower combustion temperature. The EGR system on the Nissan Terrano 2 (R20) is designed to control the formation of NOx emission by recirculating the exhaust gas into the intake manifold passage through the EGR control valve.
Decrease of nitrogen oxide emission regulations allows eligible exhaust emissions and optimize engine power and fuel consumption. Most exhaust gases out of the engine through the exhaust manifold will pass the EGR valve and EGR cooler, where it will be cooled. The cooled exhaust gas will be sent back into the intake system and mixes with air intake.
The following schematic illustrates the 2006 Nissan Terrano 2 (R20) EGR system Wiring Diagram: