Evaporative Emission System

The evaporative emission system has been designed to minimize the release of hydrocarbons from the fuel system into the atmosphere. The evaporative system components all work together with the ECM to prevent fuel vapor from escaping and route it to the intake manifold to be burned during normal combustion.

The leak detection system checks the integrity of the evaporative emission system by pressurizing system.

• When leak detection is activated, a pump pressurizes the evaporative system.
• During the leak diagnosis, the system is monitored for a specific time period. If the pressure does not drop a specific amount during the time period, the system is considered to be sealed.
• If the pressure drops greater than a specified amount during a specific time period, the system is pressurized once more. The engine control module measures the time until the pressure drops again. The control module uses the measured value to determine the size of the leak.

Leak diagnosis is activated automatically shortly following every engine start. If a malfunction is determined, an entry is made to the DTC memory. The Malfunction Indicator Lamp in the instrument cluster is illuminated if the malfunction is recognized for two subsequent starts.

For all evaporative system component locations, hose routing, removal/installation procedures and torque specifications, refer to the service information.