P0440 on Mazda
Evaporative Emission Control System Malfunction
P0440 on Mazda vehicles indicates evaporative emission control system malfunction. Au7o has documented this code across 2 Mazda models — most commonly on Mazda3, Mazda5. This code indicates a general malfunction in the Evaporative Emission Control (EVAP) system, which captures fuel vapors from the gas tank and routes them to be burned by the engine instead of escaping into the air. The computer ran a self-test and detected the sealed vapor system isn't holding pressure or vacuum correctly, often signaling a leak somewhere in the system. The most frequent and easiest cause is a loose or faulty gas cap. The car will run normally, but it will fail an emissions test and may smell faintly of fuel. Typical repair costs on Mazda range from $80 to $1,800, depending on the specific model and root cause.
Common Causes of P0440
- •Loose, damaged, or missing gas cap
- •Cracked or disconnected EVAP hose
- •Faulty purge valve/solenoid
- •Faulty vent valve/solenoid
- •Leaking charcoal canister
- •Damaged fuel tank filler neck or seal
- •Faulty leak detection pump or pressure sensor
P0440 on Mazda by Model
Mazda Mazda3(1 issue)
- EVAP Purge Valve Failure and Fuel Odor2014-2018
Third-generation Mazda3 models with the SkyActiv 2.0L and 2.5L engines experience premature EVAP canister purge valve failure. The valve can stick open, flooding the engine with fuel vapors and causing rough idle, stalling, and a strong fuel smell. Conversely, a stuck-closed valve prevents the EVAP system from purging, triggering check engine lights for evaporative system leak codes.
Mazda Mazda5(1 issue)
- A/C Evaporator Core Leak2006-2015
The A/C evaporator core in the Mazda5 develops pinhole leaks from internal corrosion, causing refrigerant loss. The evaporator is located behind the dashboard, making replacement extremely labor-intensive. Corrosion is accelerated by moisture trapped in the cabin air filter area and infrequent cabin filter replacement.
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View P0440 across all makes →Frequently Asked Questions
What does P0440 mean on Mazda?▼
P0440 stands for "Evaporative Emission Control System Malfunction." This code indicates a general malfunction in the Evaporative Emission Control (EVAP) system, which captures fuel vapors from the gas tank and routes them to be burned by the engine instead of escaping into the air. The computer ran a self-test and detected the sealed vapor system isn't holding pressure or vacuum correctly, often signaling a leak somewhere in the system. The most frequent and easiest cause is a loose or faulty gas cap. The car will run normally, but it will fail an emissions test and may smell faintly of fuel. On Mazda specifically, this code is documented across 2 models.
What causes P0440 on Mazda vehicles?▼
Common causes on Mazda: Loose, damaged, or missing gas cap, Cracked or disconnected EVAP hose, Faulty purge valve/solenoid, Faulty vent valve/solenoid, Leaking charcoal canister. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0440 on a Mazda?▼
Repair costs on Mazda range from $80 to $1,800, depending on the specific model and root cause.
Which Mazda models have P0440 documented?▼
Au7o has documented P0440 on 2 Mazda models: Mazda3, Mazda5.