Circuit Description

Evaporative (EVAP) emission system includes following components: fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, vapor lines, fuel cap, EVAP emission canister, purge lines, and EVAP purge solenoid.

A leaking purge solenoid, EVAP purge and engine vacuum lines switched at EVAP purge solenoid, or EVAP purge solenoid driver circuit shorted to ground, will set DTC P1441.

Conditions required to set DTC are:

• No IAT, MAP, ODM, or TP sensor DTCs set.
• BARO greater than 70 kPa.
• Engine speed 650-5000 RPM.
• IAT 50-158°F (10-70°C).
• Difference between ECT and IAT less than 18°F (10°C).
• EVAP canister Pulse Width Modulation (PWM) less than 3 percent.
• EVAP purge vacuum switch open.
• Conditions present for longer than 4 seconds.