EMISSION CONTROL
TSB Revision
ENGINE AND EMISSION CONTROL
17-109
EVAPORATIVE EMISSION VENTILATION
SOLENOID CHECK
M1173007800143
Refer to Evaporative Emission Canister and Fuel Tank Pres-
sure Relief Valve
− Inspection − Over Vent Valve Module Check
P.17-118
.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
GENERAL DESCRIPTION (EXHAUST GAS RECIRCULATION SYSTEM)
M1173005200275
The exhaust gas recirculation (EGR) system lowers
the nitrogen oxides (NOx) emission level. When the
air/fuel mixture combustion temperature is high, a
large quantity of NOx is generated in the combustion
chamber. Therefore, this system recirculates part of
exhaust gas from the exhaust port of the cylinder
head to the combustion chamber through the intake
manifold to decrease the air/fuel mixture combustion
temperature, resulting in reduction of NOx. The EGR
flow rate is controlled by the EGR valve for
driveability quality.
OPERATION
When the engine coolant temperature is low, when
the engine is at idle or when a wide open throttle
operation is performed, the EGR valve is kept
closed, achieving no EGR.
After warming up of the engine, the EGR valve can
be opened by the engine control module (ECM) or
powertrain control module (PCM).
The ECM or PCM monitors the EGR system and illu-
minates the check engine/malfunction indicator lamp
to indicate that there is a malfunction.