P0440: EVAP System
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - this affects fuel vapour containment, not how the engine runs.
Symptoms
- Check engine light with no change in driving
- Occasional fuel smell
- Emissions test failure
Likely causes, most common first
- Fuel cap loose, worn or the wrong part
- Cracked or disconnected vapour hose
- Purge or vent valve leaking
- Charcoal canister cracked
Read P0440 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0440 is the general fault for the evaporative emissions system - the sealed network of hoses, valves and a charcoal canister that stops fuel vapour escaping from the tank into the air. Nothing about it affects power or reliability, which is why the car drives exactly as it did before.
Start with the cheapest possibility every time. A fuel cap that is loose, aftermarket, or has a hardened seal accounts for a large share of these codes, and the fix costs less than the diagnostic time. If the cap is sound, a smoke test through the system finds a leak in minutes where hours of visual inspection may not.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0440
“Check engine light code P06DE occurred 04/2022. Oil pressure sensor removed And replaced. Check engine light code P06DE occurred 05/2022. Performed 2nd oil change in less than 1 month. Check engine light code P0440 occurred 10/2022. Evaporative System Integrity Monitor Switch replaced. Check engine light code P06DE occurred 03/2023. Oil pressure sensor removed And replaced (including R&I Lower intake Manifold). Check engine light code P06DE occurred 04/2023 Oil pressure sensor removed And replaced. Replaced oil pump and gaskets needed for reassembly of engine. Check engine light code P0523 occurred 05/2023. Replaced transfer case module. Check engine light code P0523 occurred 06/2023.”2015 Jeep Grand Cherokee · Apr 2022
“Check Engine light came on. Code states P0440 Evaporative Emission Systems. However, i looked to see if recall was issued for my vehicle and it states a recall was issued for this but not my vehicle vin number.”2016 Dodge Durango · Feb 2022
“69000 miles, check engine light came on. Codes p0440 was thrown 2x. I already replaced purge valve at my own cost. I also informed dodge. They won't fix it unless I pay for diagnosis. Which I already had one done. Also headlight bulb dropped at 38k miles and I informed dodge and mechanic. She said I didn't have the warranty on it and they wouldn't replace unless I paid full cost”2018 Dodge Durango · Aug 2020 · 68,900 mi
Show 7 more owner reports
“Car shut off while driving, there was a strong gasoline odor coming from underneath the vehicle, turned back on after a few minutes,gas cap light came on, went to autozone to run scanner and got code p0440, checked all evap components and lines and noticed something loose on top of fuel tank, rollover valve popped off and there was fuel all around it... I'm lucky there were no sparks from anything,had a full tank!”2007 Chrysler 300 · Dec 2018 · 77,118 mi
“Receiving codes p0440 and p0446, vehicle has 118244 miles currently. Bought car brand new. Check engine light came on with a slight smell of fumes, while driving. Replaced fuel cap first per autoparts store diagnostics and had codes cleared. Check engine light and smell reappeared. A week later replaced fuel filler pipe and vent hoses. Symptoms returned, sames codes registering. Had codes cleared but light returns. Have read that certain types of the same models and year vehicles have been recalled for ecm replacements, if this is the issue, I would like to be notified as soon as possible as no one else seems to be able to solve this mystery.”2003 Toyota Corolla · Dec 2018 · 117,300 mi
“2000 regal buick with low mileage didn't pass nh state inspection because of code p0440 evaporation emission control system. When looking at gm recall there were 248 other 2000 buick recalls with the same issue reported to general motors.this code has to do with the fuel system, gas lines and storage tank and can be very dangerous and catch the car on fire.I did call gm and filed a claim but they really don't care.also there is a steering/suspension steering linkage free play. When doing research on this there was a recall (76128) and 979 people also reported this issue. *tr”2000 Buick Regal · Mar 2013 · 137,000 mi
“When fueling vehicle, fuel spits back and overflows every time nearing full tank. Also sets check engine light p0440. Potential fire hazard. *tr”2007 Jeep Wrangler · Jan 2013 · 45,000 mi
“A large amount of fuel violently erupts from tank mouth when filling and overflows onto the vehicle, ground & myself. This occurs at each complete fill-up. This 2005 jeep wrangler sporadically trips obd-2 check engine codes for emission evaporative components, in the p0440-p0456 range. *tr”2005 Jeep Wrangler · Jan 2012 · 85,300 mi
“1) check engine light! 2) advised the gas cap was probably not tightened properly system reset and light appeared in 100 miles. Technician found gm service bulletin 05-06-04-014a: info - diagnostic aids for trouble codes p0440, p0455 & / or p0442 fuel was leaking from the crack 2002 - 2004 envoy may have issues with a crack in the gas tank filler neck 3) replaced fuel tank at my expense as gm would do nothing. Technician advised that the filler neck broke off completely with minimal pressure *tw”2003 GMC Envoy · Dec 2009 · 97,473 mi
“Fuel filler tube corrosion causes leak of fuel and fuel vapor. Check engine light illuminates code p0440 (evap emissions malfunction). Fuel filler tube and valve assembly parts cost is $200. Labor $275. Common problem on subarus that should be investigated and recalled due to fuel vapor leakage poses an environmental safety hazard. *tr”1999 Subaru Outback · Aug 2009 · 150,000 mi
Cars that report P0440 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0440?
Yes - this affects fuel vapour containment, not how the engine runs.
How much does it cost to fix P0440?
Typical US repair costs range from $20 for the simplest fix (fuel cap) to $900 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P0440. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.