The P0456 code means the fuel vapor system failed its own leak test by a very small margin. The engine runs the same, nothing drips and nothing smells, yet the check engine light stays on and the car will not pass an OBD emissions test. Most of the time the fix is cheap. The NHTSA records show which cars are the exceptions, and one of them has an open recall.
What the P0456 code means, and where the leak hides
Fuel gives off vapor in the tank. The EVAP system stores it in a charcoal canister and later lets the engine draw it in and burn it. To make sure none of it escapes, the computer seals the whole system now and then and checks that it holds. P0456 is the smallest failure that test reports, a hole about 0.020 inch (0.5 mm) across.
A leak that small rarely shows up on a visual check. That is why shops use a smoke machine, which fills the system with visible vapor at low pressure so the escape point shows itself. Smoke testing an EVAP system leak takes minutes once the car is on a lift.
P0456 code causes in carmakers’ bulletins
NHTSA holds 627 manufacturer bulletins that mention P0456. Counting each revision once and keeping only repair bulletins for US vehicles leaves 460.
What manufacturers prescribe for P0456
Share of 460 distinct repair bulletins that mention P0456, by the fix they call for
Source: NHTSA manufacturer communications (technical service bulletins), received 2010–2026. Revisions of the same bulletin are counted once. A bulletin can call for more than one fix.
Software updates lead the chart, but that comes from one group of carmakers. The Stellantis brands, led by Jeep and Dodge, issued 249 of the 460 bulletins, and 231 of those are engine computer updates that list P0456 among dozens of other codes. In the 211 bulletins from every other carmaker, software appears in only 23. There, the fuel cap and filler neck come first (18), followed by the vent valve (13), the leak detection module (10) and the purge valve (9).
| Bulletin | Vehicles | What it says |
|---|---|---|
| 01-005-19-3548 Mazda · Jan 2019 | CX-3 2016–2019 CX-5 2013–2019 CX-9 2007–2019 MAZDA3 2011–2019 +1 more models | Mazda's own bulletin says the most likely cause of P0456 is a fuel cap that was not closed all the way after filling up. |
| T-SB-0086-16 Toyota · Jul 2016 | Corolla 2014–2016 | On the 2014 to 2016 Corolla the cap may not click or spring back when it is tightened, and the filler neck can sit out of position. |
| ATS170206 Honda · Jun 2017 | Pilot 2016 Ridgeline 2017 | When the leak is at the filler neck, Honda says not to replace the whole fill pipe. Replace the mis-fuel inhibitor and the flap unit inside it. |
| NTB17-082 Nissan · Jul 2017 | 370Z 2009–2017 Altima 2007–2013 Maxima 2009–2017 Nv 2012–2016 +6 more models | The leak is at the O-ring where the vent control valve mounts to the canister. Nissan revised this bulletin five times through 2022 to add models. |
| 20-01-020H Hyundai · May 2020 | Sonata Hybrid 2016–2019 | On the 2016 to 2019 Sonata Hybrid, salt deposits form inside the leak detection sensor, mostly in coastal California under marine fog. |
| TSB_FUE046 Kia · Jun 2020 | Optima 2017–2019 Optima Hybrid 2017–2019 | A combined bulletin and service action for the Optima Hybrid: replace the fuel tank air filter and, if the leak test still fails, the leak detector. |
| 25-002-15 REV-B Dodge · Oct 2015 | Durango 2015 | The hose on the purge valve of the 2015 Durango can split and keep the system from sealing. The same bulletin covers the Jeep Grand Cherokee. |
| TSB 19-2207 Ford · Jun 2019 | C-max 2013–2017 Fusion Energi 2013–2017 Fusion Hybrid 2013–2017 | On the 2013 to 2017 C-Max and Fusion Hybrid and Energi, the canister purge valve may not seal. The repair includes a software update. |
Which cars set P0456 most
P0456 by make
Owner complaints and service bulletins that mention P0456, top 10 makes
Owner complaintsService bulletins
Bulletins are counted per make and bulletin number; one bulletin can cover several models and years.
| Make | Model | Complaints |
|---|---|---|
| Ford | Focus | 32 |
| Ford | Escape | 12 |
| Ford | Fusion | 10 |
| Ford | Edge | 10 |
| Jeep | Grand Cherokee | 8 |
| Ford | Fiesta | 5 |
| Mercedes-Benz | Amg E55 | 4 |
| Ford | Mustang | 4 |
| Mercedes-Benz | E350 | 3 |
| Volkswagen | Passat | 3 |
Ford Focus 2012 to 2018: the purge valve recall
Ford accounts for 78 of the 177 complaints, and the Focus alone for 32. Every one of those 32 is a 2012 to 2018 model. In 24 the owner mentions a recall, in 17 the purge valve, and in 15 the engine stalled or shut off while driving.
These are the cars in NHTSA recall 18V-735 (Ford 18S32). It covers 2012 to 2018 Focus models with the 2.0L engine, where the canister purge valve can stick and pull too much vacuum on the fuel tank. Dealers update the engine computer software and replace the purge valve if codes are present, along with the canister, fuel tank or fuel pump module when they are damaged. In 2026 Ford added a second recall, 26V-369 (Ford 26S40), for cars that were repaired incorrectly under the first one and can still stall. Owner letters went out on July 29, 2026.
If your Focus shows P0456 together with P1450 or P144A, use the vehicle finder on this page or your VIN on the NHTSA recall site before paying for parts.
Jeep, Dodge, Chrysler and Ram: ask for the software update first
These four brands have 37 complaints but more bulletins than every other carmaker combined. Most are engine computer updates that rewrite the leak test itself. If a Stellantis vehicle sets P0456 and the cap is fine, ask the dealer whether a newer calibration exists for your VIN. The Grand Cherokee and Durango also have a hardware bulletin for a split hose on the purge valve.
Nissan and Infiniti: the vent valve O-ring
Nissan’s bulletin for P0456 points at one spot: the O-ring where the vent control valve mounts to the canister. It covers a long list of models from the 350Z to the Altima and Armada, and Infiniti has a matching version. The bulletin tells technicians to rule out a loose cap first.
Hybrids near the coast: salt in the leak detector
Hyundai and Kia hybrids use a natural vacuum leak detector (NVLD) in the vent path. Hyundai’s bulletins for the 2011 to 2019 Sonata Hybrid describe salt deposits forming inside it, mostly in coastal California where marine fog is common. Kia has service actions for the Optima Hybrid and Niro that replace the fuel tank air filter and, if the leak test still fails, the detector.
P0456 complaints by model year
Model years 2005–2024; peak year 2013 highlighted
Owners who gave their mileage reported a median of 71,126 miles.
How to find an EVAP system leak, step by step
The order below starts with the cheapest checks and the most common causes in the bulletins.
- Remove the fuel cap and look at the rubber seal for cracks or flat spots. Refit it and turn it until it clicks. If it is an aftermarket cap, replace it with the carmaker’s part.
- Clear the code and drive normally for a few days. The leak test runs only under certain conditions, often after the car has sat overnight with the tank partly full.
- If the code returns, look at the filler neck where it meets the tank and at the hoses you can reach, especially near the canister.
- Have a shop run a smoke test. It finds leaks in parts you cannot see, such as the vent valve O-ring or a cracked canister.
- Ask a dealer to check your VIN for recalls and bulletins before agreeing to replace a valve or the canister.
EVAP leak repair cost and who pays
The evap leak repair cost depends on which part fails, and the bulletins show how wide that range is. A fuel cap is the cheapest fix. A purge valve or vent valve costs more. A charcoal canister, a fuel tank seal or a fuel pump module costs the most, mostly in labor, because the tank often has to come down.
Before paying, check two things. Recall repairs are free, which covers the Ford Focus above. Federal law also requires carmakers to cover emission control parts for 2 years or 24,000 miles, and some states require longer coverage.
Symptoms that come with P0456
What owners describe alongside P0456
Share of 177 NHTSA owner complaints that mention P0456
Counted by phrases in the complaint text. One complaint can mention several things.
Almost every complaint starts with the check engine light. Stalling comes next, and 21 of those 32 complaints are Fords, which is the purge valve problem above. A fuel smell appears in 22 complaints. A small vapor leak by itself does not cause stalling or rough running, so if you have those symptoms with P0456, look for a second fault or an open recall.
Can you drive with a P0456 code?
A strong smell of fuel is a reason to stop and check the cap and filler area.
P0456 alone means a leak too small to smell. Liquid fuel or a strong odor points to a bigger problem than this code describes.
With the light on and no other symptoms, the car is fine to drive while you sort out the cause. The one exception is the 2012 to 2018 Ford Focus with the 2.0L engine, where the same fault can stall the engine in traffic. Have the recall done first.
P0456 questions owners ask
How do you fix code P0456?
Check the fuel cap first: tighten it until it clicks, look for a cracked seal, and replace it if it is an aftermarket cap. Clear the code and drive for a few days, because the leak test only runs under certain conditions. If the code returns, have a shop run a smoke test, which shows exactly where vapor escapes. Ask a dealer to check your VIN for recalls and bulletins before paying, since several models have a known fix.
What is the most common cause of P0456?
A fuel cap that is loose, worn or the wrong type is the most common single cause, and Mazda's bulletin names it directly. In carmakers' bulletins outside Jeep, Dodge, Chrysler and Ram, the fuel cap and filler neck come first, then the vent valve, the leak detection module and the purge valve.
How much does it cost to fix code P0456?
It depends on which part leaks. A fuel cap is the cheapest fix. A purge or vent valve costs more, and a charcoal canister or fuel tank work costs the most. Recall repairs are free, and federal law covers emission control parts for 2 years or 24,000 miles, so check both before you pay.
Is it okay to drive with a P0456 code?
In most cars, yes. A very small leak does not change how the engine runs. The exceptions are a strong fuel smell, which should be fixed soon, and the 2012 to 2018 Ford Focus with the 2.0L engine, where the purge valve fault behind this code can stall the engine. That car has an open recall.
Will code P0456 clear itself?
Often it will, if the cause was a cap left loose. The computer reruns the leak test over the next drive cycles and turns the light off after it passes several times in a row. If the light comes back, the leak is real, and an emissions test station will still see the stored code until the tests have completed.
What is the difference between P0456, P0442 and P0455?
All three mean the leak test failed. P0455 is a large leak, often a missing or open cap. P0442 is a small leak. P0456 is the smallest leak the system is built to find, about 0.020 inch (0.5 mm) across, which is why it is the hardest to locate by eye.
Check P0456 for your car
Figures on this page come from NHTSA complaint and service bulletin files received through October 2026. How we count.