On the 2002 Pontiac Sunfire, he P0440 is pointing to a fault in the EVAP (emmisions control/recovery) System. Do a full inspection of the EVAP System and the vacuum lines and make sure there are no lines with cracks, holes or loose/missing connections. Give the EVAP Canister an inspection and make sure there are no cracks holes of dents. If the visual inspections check ok, then most commonly with the P0440 is a problem with the EVAP Vent Valve. The Vent Valve and Canister are located under the vehicle, towards the rear, near the fuel filler tube. Inspect the electrical connector for any loose, broken or damaged wires. Inspect the rubber lines to/from the Vent Valve. If the visual inspection checks ok, replace the Vent Valve.
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