The Quick Answer above is the generic definition. What follows is the model-specific detail for the Audi models that log P0440.
DTC/P0440·Audi
P0440 on Audi: Causes, Symptoms and Fix Cost
Quick Answer
Low SeveritySafe to drive (short-term)Audi
P0440 on a Audi 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.
Typical repair cost, all makes€10 - €600
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Get Skanyx freeWhat does P0440 mean on a Audi?
Audi A4
2005-2024The B7 A4 with the 2.0 TFSI (EA113) and the B8 with the 2.0 TFSI (EA888) commonly trigger P0440 when the N80 purge valve fails, often in the open position. The valve is mounted on the intake manifold and is quick to replace.
What causes P0440 on a Audi?
Beyond the generic causes listed on the main P0440 page, these are the patterns noted for Audi models:
Audi A4N80 purge valve failing on B7/B8 2.0 TFSI
Audi A4Brittle EVAP hoses near the engine from heat cycling
How to diagnose P0440 on a Audi with OBD2
Follow these steps to pinpoint the root cause of P0440:
- 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
- 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
- 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 50 to 120 EUR for the diagnostic alone at a workshop
- Check the purge and vent valves: with manufacturer-level software you can command them open and closed and listen for clicking (a generic OBD2 reader cannot run these actuator tests); otherwise test them off the car with 12 V and a hand vacuum pump. A stuck-open or stuck-closed valve is a frequent cause
- 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
How much does P0440 cost to fix on a Audi? (EUR)
Estimated repair costs for P0440 in EUR, compiled across makes. Expect Audi parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Codes related to P0440
These codes are often seen alongside P0440 or point to related issues, on any make:
Looking for the full P0440 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0440 guideSkanyx · Audi
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