Circuit Description

Following components are included in Evaporative (EVAP) system:

• Fuel tank.
• EVAP canister vent solenoid.
• Fuel Vapor Pressure (FVP) sensor.
• Fuel pipes and hoses.
• Vapor lines.
• Fuel filler cap.
• EVAP emissions canister.
• Purge lines.
• EVAP canister cut valve (purge solenoid).
• EVAP service port.

EVAP leak detection diagnostic strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. PCM monitors vacuum level through FVP sensor input. At an appropriate time, EVAP canister purge valve and EVAP canister vent valve are turned ON, allowing engine vacuum to draw a small vacuum on entire EVAP system. A leak is detected by monitoring for a decrease in vacuum level over a given time period, while all other variables remain constant. A small leak in EVAP system will cause DTC P0442 to set.