P0456: EVAP System Leak Detected (very small leak)

A generic powertrain (engine and transmission) trouble code, same meaning on every brand.

Low urgency

Yes - the least urgent code in this family.

$10 - $350

typical repair range

145

NHTSA complaints mention this code

75,000

median mileage when reported, mi

Symptoms

Check engine light only, typically no other signs

Likely causes, most common first

Gas cap seal aging
Pinhole crack in an EVAP hose
Slightly leaking purge valve

Read P0456 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

P0456 flags a very small EVAP leak - down to the 0.5 mm range. These are the hardest leaks to find by eye and the least consequential to ignore short-term. The practical approach: replace an old gas cap on principle, then smoke-test if the code returns.

Because the leak is tiny, the code may come and go with temperature swings. That intermittent pattern is normal for P0456 and does not indicate anything getting worse quickly.

Repair options and cost

Gas cap$10 - $40

Smoke test + small leak repair$120 - $350

Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.

Owner reports mentioning P0456

“With only 32,885 miles, engine light came on due to (P0456) EVAP small leak. Went to an auto shop and Ford dealer for diagnostic scan. Both technicians found that there is a bit of smoke coming out from the top of the fuel tank due to a small stress crack at the port near the canister vent hose as well as a small crack below fuel pressure sensor tube. New fuel tank replacement was recommended as the crack could not be repaired. Cost to fix is $1,400 parts and $1,200 labor. This small crack nears the fuel tank seems to be a major concern for owners as it could increase the risk of vehicle fire and should be a recall by Ford for immediate remedy.”2015 Ford Mustang · Nov 2025

“The contact owns a 2021 Ford Bronco Sport. The contact received notification of NHTSA Campaign Number: 25V467000 (Fuel System, Gasoline). While driving at an undisclosed speed, the check engine warning light was illuminated, and the vehicle began shaking and hesitated while accelerating. The vehicle was taken to a dealer, where it was diagnosed, and the failure was associated with DTC: P0456 EVAP (Very Small Leak in EVAP Emission Control System). The vehicle was not repaired. The manufacturer was notified of the failure. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The failure mileage was approximately 83,191.”2021 Ford Bronco Sport · Oct 2025 · 83,191 mi

“The contact owns a 2022 Volkswagen Golf. The contact stated that while driving at various speeds, the check engine warning light remained illuminated. The vehicle was taken to an independent mechanic, and it was determined that there was a leak in the evaporative emissions system after scanning the vehicle and retrieving DTC: P0456. The contact associated the failure with NHTSA Campaign Number: 24V110000 (Fuel System, Gasoline). The local dealer was contacted; however, the vehicle was not diagnosed or repaired because the VIN was not included in the recall. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 17,000.”NHTSA complaint · Sep 2025 · 17,000 mi

Show 7 more owner reports

“Vehicle has active alerts for powertrain control module, and low boost pressure with the turbocharge along with emissions codes P0299, P0496 and P0456. The vehicle is constantly going into deep sleep mode. While driving the vehicle started to enter safe mode. And displayed an alert that said please turn ignition on. The dash and screen went black like vehicle was off but it was still running. This happened multiple times. My vehicle also will not start after pumping gas so I have to leave vehicle running every time I pump gas. My vehicle will not pass NY state inspection because of the recalls.”2020 Ford Escape · Aug 2025

“I have this car since 2019 with 8000 miles and this is the 3rd time the code came up for the evap system to be repaired. P0456. The first time it was replaced was at mileage 47084 at winner Ford dealership. On June 11th 2021. The second time it was replaced was at Winter Ford dealership on March 17th 2022 with mileage 59,678. The light just came on today and the code came up again. PO456. I now have 102,000 mi on my car. I think that this should be a recall worth looking into. Thank you”2017 Ford Fiesta · May 2025

“At only 68,000 miles, my check engine light came on with code "P0456", which indicates that my Evaporative Emission System has a leak. These leaks lead to increased emissions and fuel loss. The solution is to replace the Emission System Integrity Monitor (ESIM). The life expectancy of this part is 150,000 miles. It should not leak at less than half its life expectancy. I contacted the local dealership and they reported that there isn't a recall on this part yet.”2013 Dodge Challenger · Apr 2025

“P0236 , p0238, p007d, p0456, charged air sensor A fault, boost sensor range/performance fault, and other faults , crank car engine service now pops up everytime, clear codes pops rite back up, car stumbles ,misfires , no boost, no throttle shuts off . Only had this car a week . Performed wire splice and anything I saw that I could do to fix this . No help making payments on a car I can't drive is very frustrating. Replaced sensors. These faults pop up within 2 seconds of clearing codes and starting vehicle everytime.”2013 Ford Focus · Sep 2024

“There is an EVAP emission leak and the P0456 error states the gas cap is faulty. I had it replaced and replaced again. So I am waiting for another brand new gas cap-3rd brand new one. So 4th overall for this van. A smoke test was done and there is no leaks per the test. So if this continues after the brand new gas cap, then there should be a recall as the gas cap is an issue. Started to happen after 95,000 miles. The AWD is shut off and goes to 2 wheel drive, traction control is turned off, Check Engine light comes on and Message Check AWD system comes up on the screen. Any recommendations”2015 Toyota Sienna · Mar 2024

“My check engine light came on. I have the code P0456 indicating the evaporative emission system has a leak. This is the same code that caused a recall for 1,282,596 Ford focuses on recall #18S32. My VIN number is not in the recall, but I'm having the same problem.”2018 Ford Focus · Mar 2024

“1. The code indicates that the evaporative emission control (EVAP) system is unable to bleed up the fuel tank vacuum. p1450 2.Purge Valve needs replacement as it is sucking p0456 3. After getting gas, gar does not start Sick of being told nothing is wrong and it isn't happening to my 2018 Ford Focus. Now I have to have it diagnosed again for 280.00 when I know that my car should be included in all recalls. Yes it has been confirmed by a mechanic I am at risk constantly in this car. Yes check engine soon light keeps coming on”2018 Ford Focus · Dec 2023

Cars that report P0456 most often

Based on mentions of this code in NHTSA owner complaints.

Frequently asked questions

Can I drive with P0456?

Yes - the least urgent code in this family.

How much does it cost to fix P0456?

Typical US repair costs range from $10 for the simplest fix (gas cap) to $350 in the worst case. The right number depends on which cause your car has - see the causes list.

Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.