P0440: Evaporative Emission Control System Malfunction

P0440 is the generic OBD-II code for an evaporative emission control system malfunction. It means the ECU detected a fault in the system that captures fuel vapours from the tank and routes them to the engine. The most common trigger is a loose or missing fuel cap, but it can also indicate hose leaks, a failed purge valve, or a cracked charcoal canister.

P0440 è un codice diagnostico di guasto relativo a sistema evap, classificato con gravità low. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0440 e accende la spia motore.

Se il tuo veicolo ha attivato P0440, potresti notare uno o più di questi sintomi:

• Check engine light illuminated
• Faint fuel odour around the vehicle, especially in warm weather
• Possible failed emissions test
• No noticeable driveability issues in most cases
• Fuel cap warning indicator on some vehicles

Ecco le cause più comuni di P0440, ordinate in base alla probabilità che siano la causa del problema:

In genere sì, per brevi tragitti. P0440 is a generic EVAP fault and does not affect driveability. You can drive normally, but the check engine light will cause an automatic failure at any EU vehicle inspection. Address before your next emissions test.

Segui questi passaggi per individuare la causa principale di P0440:

1. Check the fuel cap first. Remove it, inspect the rubber seal for cracks or debris, and re-seat it until it clicks. Clear the code and drive for several cycles to see if it returns
2. Visually inspect EVAP hoses from the fuel tank to the charcoal canister and from the canister to the purge valve at the engine. Look for cracks, brittle plastic, loose clamps, or disconnections
3. Perform a smoke test on the EVAP system. Seal the system, introduce smoke, and watch for visible plumes escaping at hose connections, the canister, or the fuel tank area. Expect 40 to 100 EUR for the diagnostic alone at a workshop
4. Use a scan tool to command the purge valve and vent valve open and closed. Listen for clicking. A stuck-open or stuck-closed valve is a frequent cause
5. If the smoke test reveals no external leaks, inspect the charcoal canister for cracks and check the fuel tank pressure sensor reading with live data

I costi di riparazione di P0440 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

P0440 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:

Questi codici compaiono spesso insieme a P0440 o indicano problemi correlati: