Emission Control Systems: Description and Operation

Engine Emission Control

NOTE: Do not permanently remove or render inoperative any part of the vehicle emission control system including related hardware. Failure to comply may violate applicable state and federal law.

NOTE: The vehicle emission vacuum routing diagrams are contained in the Description and Operation subsection of the Engine Emissions Control system. For additional information, refer to Evaporative Emissions System.

The engine emission control system consists of the PCV system:

PCV System

The PCV system:

- uses intake manifold vacuum to ventilate blow-by vapors from the crankcase.

- returns the vapors to the intake manifold for combustion.

The PCV system consists of the:

- crankcase ventilation tube.

- PCV valve.

The PCV valve:

- varies the amount of blow-by vapors returned to the intake manifold based on available engine vacuum.

- prevents combustion gases backfiring into the crankcase.