The basic evaporative emission (EVAP) control system used on this vehicle is the charcoal canister storage method. This method transfers fuel vapor from the fuel tank to an activated carbon (charcoal) storage device (canister) to hold the vapors when the vehicle is not operating. When the engine is running, the fuel vapor is purged from the carbon element by intake air flow and consumed in the normal combustion process.

Gasoline vapors from the fuel tank flow into the tube labeled tank. Refer to the Evaporative Emission Canister graphic. These vapors are absorbed into the carbon. The canister is purged by PCM control when the engine coolant temperature is over 41°C (106°F), IAT reading is over 0°C (32°F), and the engine has been running a specified amount of time. Air is drawn into the canister through the air inlet grid. The air mixes with the vapor and the mixture is drawn into the intake manifold.

Canister purge is controlled by a solenoid valve that allows manifold vacuum to purge the canister. The Powertrain Control Module (PCM) supplies a ground to energize the solenoid valve (purge ON). The EVAP purge solenoid control is pulse width modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by engine operating conditions including load, throttle position, coolant temperature, and ambient temperature. The duty cycle is calculated by the PCM and the output is commanded when the appropriate conditions have been met:

An incorrect EVAP purge system flow should set a DTC P0443.

Poor idle, stalling and poor driveability can be caused by:

Check the EVAP canister for the following conditions: