System Description

WARNING: This page is about a different car, the 2005 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: System Description Chart EGR

Courtesy of NISSAN MOTOR CO., U.S.A.

This system controls flow rate of EGR led from exhaust manifold to intake manifold. The opening of the EGR by-pass passage in the EGR volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions. The EGR volume control valve remains closed under the following conditions.

Engine stopped
Engine starting
Engine idling
Low engine coolant temperature
Excessively high engine coolant temperature
High engine speed
Wide open throttle
Low battery voltage

Fig 2: EGR Component Description
Courtesy of NISSAN MOTOR CO., U.S.A.