Sable V6-183 3.0L DOHC VIN S MFI (1997)
EGR Valve: Description and Operation
Exhaust Gas Recirculation Valve
PURPOSE
The Exhaust Gas Recirculation (EGR) valve is designed to reintroduce exhaust gas into the combustion cycle lowering combustion temperatures and
reducing the formation of Oxides of Nitrogen (NOx).
EGR Flowrate
OPERATION
The EGR valve in the Differential Pressure Feedback EGR (DPFE) system is a conventional, vacuum-actuated EGR valve. The valve increases or
decreases the flow of exhaust gas recirculation. As vacuum applied to the EGR valve diaphragm overcomes the spring force, the valve begins to open.
As the vacuum signal weakens, at 5.4 kPa (1.6 in Hg) or less, the spring force closes the valve. The EGR valve is fully open at about 15 kPa (4.5 in
Hg).
Since EGR flow requirement varies greatly, providing service specifications on flow rate is impractical. The on-board diagnostic system monitors the
EGR valve function and triggers a Diagnostic Trouble Code (DTC) if the test criteria is not met. The EGR valve flow rate is not measured directly as
part of the field diagnostic procedures.
