P0440 on Subaru
Evaporative Emission Control System Malfunction
P0440 on Subaru vehicles indicates evaporative emission control system malfunction. Au7o has documented this code across 1 Subaru model — most commonly on WRX. 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 Subaru range from $300 to $900, 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 Subaru by Model
Subaru WRX(1 issue)
- Fuel Filler Neck Corrosion Causing EVAP Leaks, Fuel Smell, and Check-Engine Light2002-2007
Rust-belt GD-chassis WRX models are known for corrosion of the steel fuel filler neck and vent tubes behind the left rear wheel area. As the neck rusts through, owners notice a raw fuel smell, difficulty filling the tank, or EVAP leak codes from the compromised venting system. Subaru issued recalls and service campaigns on related Impreza models in salt-belt states because the corrosion could lead to fuel leakage.
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What does P0440 mean on Subaru?▼
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 Subaru specifically, this code is documented across 1 model.
What causes P0440 on Subaru vehicles?▼
Common causes on Subaru: 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 Subaru?▼
Repair costs on Subaru range from $300 to $900, depending on the specific model and root cause.
Which Subaru models have P0440 documented?▼
Au7o has documented P0440 on 1 Subaru model: WRX.