Exhaust Gas Recirculation: Description and Operation

CAUTION: Do not remove any part of the engine emission control system. Operating the engine without the engine emission control system intact will reduce fuel economy and engine ventilation. This will weaken engine performance and shorten engine life.

The EGR system:
- returns a small amount of exhaust gas into the engine for composition.
- reduces the overall combustion temperature and provides a significant reduction of oxide of Nitrogen (NOx).

The EGR valve (EGR valve):
- is electronically controlled by the Powertrain Control Module (PCM).
- controls the vacuum to the EGR valve.

The EGR valve:
- is connected to the exhaust manifold by the EGR valve to exhaust manifold tube.
- controls recirculated exhaust gas flow to the intake manifold.
- monitors the flow of recirculated exhaust gases through the EGR valve to exhaust manifold tube.
- returns a signal to the powertrain control module.

The amount of recirculated exhaust gas depends upon:
- engine rpm.
- intake manifold vacuum.
- exhaust back pressure.
- engine coolant temperature.
- throttle position.

The Vehicle Emission Control Information (VECI) decal:
- is located on the hood.
- lists the exhaust emission control system information.