hello, my problem is a code P0440 (Dodge Neon SE 2003)the black box and filter replacement(new),diagnostic all code is P0440 and Check Engine Light in instrument panel
The trouble code P0440 means the Evaporative emission control system is malfunction. This malfunction may have been caused by a number of different things including, a loose or missing gas cap, a vacuum leak, a faulty purge valve, an issue with your charcoal canister, incorrect fuel pressure, or electrical issues.
I would recommend having your entire EVAP system inspected by a mechanic who is proficient in diagnosing emissions issues. The most likely cause of this issue is either a loose gas cap or a vacuum leak.
Sometimes the issue is very obvious and may be spotted just by opening the hood. It is possible that a hose may have come loose causing the trouble code to be stored and the Check Engine Light to come on. For a proper diagnosis, consider YourMechanic, as a certified technician from YourMechanic can come to your car’s location to inspect the Check Engine Light and make proper adjustments or repairs.