Evaporative Emission System

The EVAP system has been designed to minimize the release of hydrocarbons from the fuel system into the atmosphere. The EVAP system components work together with the ECM to prevent hydrocarbons from escaping to the atmosphere and store them in a charcoal canister.

The leak detection system checks the seal integrity of the EVAP system.

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

Leak diagnosis is activated automatically shortly following a cold engine start. If a malfunction is determined, an entry is made to the DTC memory. The MIL is illuminated if the malfunction is recognized for two subsequent starts.

For all EVAP system component locations, hose routing, removal/installation procedures and tightening specifications, refer to the Service Information.