Evaporative Emission Control System

As a part of the fuel system, all vehicles are equipped with fuel vapor evaporative emission control systems to meet federal requirements in effect at the time of production.

The fuel tank evaporative emission system allows for controlled release of fuel tank pressure through the Evaporative Emissions canister (EVAP canister). Under normal operating conditions, this system will allow sufficient venting to prevent a build-up of internal fuel tank pressure.

Some operating conditions may cause temporary build-up of internal fuel tank pressure. Some of these conditions are as follows:
- On warm or hot days, parking the vehicle after filling the fuel tank. The fuel is cool from underground storage and vaporizes rapidly when warmed.
- Parking after driving over rough roads, washboard, or other harsh surfaces, after filling the fuel tank. Agitation of fuel increases vaporization.
- Climbing long grades, especially while towing a trailer or while fully loaded.
- Parking after driving long distances in high temperature conditions.

A normally-functioning fuel tank evaporative emission system will relieve the pressure build-up.

No service is required if these conditions caused the concern. A blocked fuel tank evaporative emission system can cause abnormal fuel tank pressure and must be serviced.

Most components of the evaporative emission control system are serviced by a simple nut, bolt or screw for part removal and installation.

If pushpins are removed, they must be replaced with new pins.