Fuel Tank Evaporative Emission System

This systems consists of:

• Fuel tank and filler pipe
• Pressure/vacuum relief fuel cap
• Fuel tank vapor valve assembly with open flow to vacuum and pressure
• Vapor tube and hoses
• Carbon canister

Engine Evaporative Emission System

This system consists of:

• Purge control solenoid (some vehicles)
• Solenoid vent valve and purge regulator valve (some vehicles)
• Thermactor idle vacuum valve (TIV)
• Carbon canister

Not all of these components are used on any one system, since usage depends on the calibration of the vehicle.

System control and operation are accomplished through separate basic functions in the system:

1. Fill control vent system.

2. Tank vapor venting and storage system.

3. Fuel vapor purge system.

4. Pressure and vacuum relief system.