Exhaust Gas Recirculation: Description and Operation

Vacuum Hose Schematic:

DESIGN AND LOCATION
A single stage EGR valve (89) is bolted front of engine, near the intake manifold. The LH control module (N3/1) controls the introduction of exhaust gases via the EGR switchover valve (Y27).

EGR Valve (89):

OPERATION
The switch-over valve is activated (by the LH control module) at coolant temperatures above 65 °C (149 °F) and only if the engine is between the idle and full load condition. When the valve opens, intake manifold vacuum reaches the EGR valve and opens it. Some exhaust gases now flow from the exhaust manifold back into the intake manifold.