6E1–318
X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
acceptable for proper EGR system operation, the ECM
will set DTC P0404.
GENERAL DESCRIPTION —
POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM
Crankcase Ventilation System Purpose
The crankcase ventilation system is used to consume
crankcase vapors in the combustion process instead of
venting them to the atmosphere. Fresh air from the
throttle body is supplied to the crankcase and mixed with
blow–by gases. This mixture is then passed through the
positive crankcase ventilation (PCV) port into the intake
manifold.
While the engine is running, exhaust gases and small
amounts of the fuel/air mixture escape past the piston
rings and enter the crankcase. These gases are mixed
with clean air entering through a tube from the air intake
duct.
028RX003
During normal, part–throttle operation, the system is
designed to allow crankcase gases to flow through the
PCV valve into the throttle body to be consumed by
normal combustion.
A plugged valve or PCV hose may cause the following
conditions:
D
Rough idle.
D
Stalling or slow idle speed.
D
Oil leaks.
D
Sludge in the engine.
A leaking PCV hose would cause:
D
Rough idle.
D
Stalling.
D
High idle speed.