The Evaporative Emission (EVAP) System
WARNING: This page is about a different car, the 2004 Ford RV Cutaway, 2004 Ford Econoline, 2004 Ford E450 Super Duty, and 2004 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Prevents hydrocarbon emissions from reaching the atmosphere.
- Stores fuel vapors in the evaporative emissions (EVAP) canister that are generated during vehicle operation or hot soak, until they can be consumed by the engine during normal engine operation.
- Routes the stored fuel vapors to the engine during engine operation.
- Is controlled by the powertrain control module (PCM) which uses various sensor inputs to calculate the desired amount of EVAP purge flow. The PCM regulates the purge flow, induced by the application of intake manifold vacuum, by varying the duty cycle applied to the canister purge valve.
- Has an evaporative emission test port for test purposes.
THE EVAPORATIVE EMISSION (EVAP) SYSTEM TEST PORT:
- Is located near the EVAP canister purge valve.
- Is used to connect the Evaporative Emission System Leak Tester to the EVAP system.