P0440: How to Diagnose & Fix — Evaporative Emission Control System Malfunction
14 vehicles · 9 makes · $20-$1,800 repair
How to diagnose and fix P0440: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Chrysler 300 · 2011–2023
Evaporative emission control system develops small leaks triggering P0456 code. Most commonly failed gas cap, chaffed EVAP purge pipe harness, or failed purge solenoid. Triggers check engine light and prevents emissions testing pass.
Common Symptoms
- Check engine light with P0456 code
- "Gas cap" warning even with cap tight
- Fuel smell near vehicle
- Failed emissions test
- No performance or drivability issues
How to Fix
Start with gas cap replacement ($20-40). If code returns, smoke test EVAP system to locate leak. Common fixes: replace purge solenoid, repair chaffed wiring harness, or replace cracked EVAP hoses.
Sources for this issue (1)
Dodge Journey · 2009–2020
AC compressor fails due to inadequate lubrication, leaky seals, and internal mechanical failure. Evaporator develops leaks from age and moisture. Condenser prone to damage from road debris. Lack of lubrication from leaks causes compressor seizure.
Common Symptoms
- AC blows warm air
- AC works intermittently
- Compressor clutch not engaging
- Loud grinding or squealing from compressor
- Musty odor from vents (evaporator mold)
How to Fix
Diagnose AC system to identify leak source. Replace failed compressor ($400-800), evaporator ($300-600), or condenser ($200-400) as needed. Flush AC system when replacing compressor. Replace receiver/drier whenever system opened.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Mopar 55111410AF complete A/C compressor
Replace a compressor confirmed failed on the listed configuration Fitment: 2016-2020 Journey 2.4L on the product fitment table; not the 3.6L compressor Live OEM direct-product page when checked
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
Subaru WRX · 2002–2007
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.
Common Symptoms
- raw fuel smell near left rear of car
- check engine light with EVAP leak code
- difficulty filling fuel tank
- visible rust on filler neck
- fuel seepage after fill-up
How to Fix
Inspect the filler neck and vent pipes by removing the left rear wheel and splash shield, looking for rust perforation, dampness, or fuel staining. Repair usually requires replacing the filler neck assembly and associated hoses/clamps; heavily corroded fasteners may need cutting. After repair, clear EVAP codes and verify the system seals with a smoke test.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru 42066FE100 Fuel Filler Pipe
complete rear filler pipe after corrosion/perforation is confirmed Fitment/availability: 2005-2007 Impreza WRX filler-neck branch; supersedes 42066FE060, confirm VIN and associated hoses/clamps Fitment/availability: ships in 1-3 business…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipCheck recall eligibility by VIN first, especially for cars originally sold in salt-belt states.
Toyota Highlander · 2008–2019
Kia Rio · 2001–2011
Find P0440 by make
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P0440 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0440 mean?
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.
What are the most common causes of P0440?
The most common causes of P0440 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0440?
Repair costs for P0440 range from $20 to $1,800, depending on the vehicle and root cause.
Which vehicles are affected by P0440?
Au7o has documented P0440 across 14 vehicle models from 9 manufacturers: Chevrolet, Chrysler, Dodge, Hyundai, Kia, Nissan, Pontiac, Subaru, Toyota.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.