Evaporative Emissions System: Description and Operation

Evaporative Emission System:

The fuel evaporative system consists of the fuel vapor valve, check valve (two-way), charcoal canister, purge solenoid valve, Powertrain Control Module (PCM), and input devices. The amount of evaporative fumes introduced into the engine and burned is controlled by the solenoid valve to correspond to the engine's operating conditions. To provide the best engine performance, the solenoid valve is controlled by the PCM.

Operation
The purge solenoid valve is controlled by duty signals from the PCM to perform purging of the charcoal canister. Purging is done when these conditions are met:
- After warm up
- Driving in gear
- Accelerator pedal depressed (closed throttle position switch OFF)
- Heated oxygen sensor functioning normally