Key takeaways
P0456 means the engine computer found a very small EVAP leak, defined by Ford as a 0.020-inch leak, during its own leak test. It is usually safe to drive with a steady light, but the leak can be hard to find, so start with the gas cap, check for carmaker bulletins and expect a smoke test if the cap isn't the cause.
- 01Beyond the cap, the usual culprits are a damaged filler neck, a cracked hose, and a purge or vent valve that no longer seals.
- 02Toyota, Acura, Subaru, Ford, Nissan, Kia and Hyundai have all issued P0456 bulletins, and some of the fixes are software updates rather than new parts.
- 03California's Bureau of Automotive Repair lists P0442 and P0456 as the top permanent codes for gasoline and flex-fuel cars, and permanent codes fail Smog Check on 2010 and newer models.
- 04RepairPal puts a purge valve at $210 to $251 and a charcoal canister at $558 to $643, and Advance Auto Parts puts a shop smoke test at $60 to $150.
This guide belongs to our OBD2 guide: most common codes section, which covers the wider topic.
A P0456 code means your car sealed its evaporative emission control (EVAP) system for a leak test and found a very small one. Ford's OBD system operation summary defines it as a 0.020-inch leak found by a test that runs after you switch the engine off, and the car usually drives exactly as before.
That small size is the problem: a tired cap seal, a leaky purge valve or a leaking vent valve O-ring can hide even from a smoke machine.
The purge valve is also the only EVAP part in our table of the most common OBD2 codes and their repair costs, at a $172 average, though that row lists purge-flow codes rather than P0456.
P0456 Quick Answer: Meaning, Severity and Cost
P0456 stands for "Evaporative Emission System Leak Detected (Very Small Leak)." With a steady light, no strong fuel smell and a car that runs normally, it is safe to drive while you track down the leak.
| Item | Detail |
|---|---|
| Code | P0456, Evaporative Emission System Leak Detected (Very Small Leak) |
| Leak size | About 0.020 inch |
| Most likely causes | Gas cap seal, EVAP hose, purge valve, vent valve |
| Severity | Moderate: safe to drive, but fix it before an emissions test |
| Typical repair cost | $5 to $15 for a DIY cap, up to $558 to $643 for a shop canister replacement |
Code name from RepairPal and Mitsubishi, leak size from Ford and Advance Auto Parts' P0455 guide, severity from RepairPal. Cap price from Advance; canister cost is a RepairPal national estimate updated September 3, 2026, before taxes and fees.
Advance Auto Parts' P0456 guide says a small EVAP leak does not affect engine performance or safety, but recommends a repair so the light can flag the next fault.
How P0456 differs from P0455 and P0442
Ford draws the lines clearly. Its computer sets P0455 when it can't reach the first test vacuum at all and P0442 for a 0.040-inch leak, while P0456 is a 0.020-inch leak caught by a separate engine-off test.
Advance's P0455 guide says large leaks are often found by eye or by a hiss, while a P0456 leak usually needs a smoke machine.
For the large-leak code, see our P0455 large leak code guide, which covers disconnected hoses and stuck-closed purge valves.
Why Is a Very Small EVAP Leak So Hard to Find?
The hole is tiny, the pressure change it causes is tiny, and the test that looks for it runs only when conditions line up.
A tiny hole means a tiny pressure change
EPA's 30-vehicle study of OBD II evaporative monitors shows how recent this limit is: OBD II cars from 1996 to 1999 only had to flag holes of 0.040 inch or larger, and the 0.020-inch requirement phased in from 2000 through the 2002 model year.
CARB's 2002 OBD II rulemaking notes point out that a 0.040-inch leak is approximately four times as large as a 0.020-inch leak. They add that the 0.040-inch monitor generally runs more often than the 0.020-inch one.
Ford's engine off natural vacuum (EONV) test shows how small the signal is. As the tank's temperature changes after you park, a sealed tank builds a little pressure or vacuum. Ford sets P0456 when it builds less than 0.75 inch of water pressure and less than 0.50 inch of water vacuum within 45 minutes.
The test runs only under narrow conditions
Each carmaker sets its own entry conditions, and they are narrow.
| Test | When it runs | Fuel level | Temperature | Other conditions |
|---|---|---|---|---|
| Ford EONV, 2019 models | Key off, up to 45 minutes after shutdown | 15% to 85% | 40°F to 95°F at start-up | 3.5 to 6 hour soak, 20 to 90 minutes since engine start, up to 2 runs a day |
| Mitsubishi P0456 monitor | Engine running, once per driving cycle | 40% to 85% | Coolant and intake air 97°F or less at start, fuel tank above 91°F | Barometric pressure above 22.4 inHg |
| General guidance, NYVIP3 | Varies by vehicle | 1/4 to 3/4 full | 30°F to 95°F | Parked at least 8 hours, no EVAP code stored |
From Ford's 2019 OBD System Operation Summary, Mitsubishi's P0456 service procedure and New York's NYVIP3 EVAP monitor page. Other carmakers use different values.
Mitsubishi's P0456 service procedure adds that its leak limit varies with fuel temperature and fuel level.
New York's NYVIP3 EVAP monitor page says some vehicles run the monitor only during highway cruising at 45 to 65 mph for at least 10 minutes at light throttle.
CarParts.com's P0456 guide says the test typically won't run unless the tank is 15 to 85 percent full, so drivers who keep it topped off may rarely see the code.
Some leaks hide during testing
GM's EVAP leak bulletin 21-NA-124 says some leaks show up only under pressure and some only under vacuum, so test both ways. Audi's Q7 bulletin likewise blames static or sporadic air leaks.
P0456 Symptoms
Usually the check engine light is the only sign. O'Reilly Auto Parts' P0456 page says a small EVAP leak is not typically enough to cause noticeable performance problems.
When there is more, watch for these signs:
- A steady, not flashing, light and a failed emissions inspection, both listed by Advance
- A faint gas smell or slightly lower fuel economy over time, as AutoZone's P0456 guide notes
- A gas cap that won't click or spring back, reported on some 2014 to 2016 Toyota Corollas
- A cap with a loose or stick-slip feel, or a TIGHTEN FUEL CAP message, on some Acura models
- A hard start or loss of engine rpm right after refueling, which Ford fixes with a new purge valve
From Advance Auto Parts, AutoZone, Toyota bulletin T-SB-0086-16, Acura bulletins 14-006 and 14-053, and Ford bulletin 16-0075.
What Causes P0456? Most Likely First
Start with the gas cap, then work toward the valves and canister. Advance ranks the cap first, then hoses, the purge valve, the vent valve, the canister and the filler neck.
The gas cap seal and filler neck
A cap can look fine and still leak. RepairPal's gas cap estimate says a cap that looks acceptable gets a pressure test with a fuel cap pressure tester, and that expecting more than 100,000 miles from one cap is not likely realistic.
Sometimes the design is at fault. Acura's fuel cap bulletin 14-006 says the cap gasket on several 2011 to 2013 models creates too much friction to seal, so caps with a black gasket get replaced with ones that have a brown gasket.
Mitsubishi also lists incorrect cap relief pressure. At the neck, Advance says corrosion is more common in northern climates, and FCA has technicians look for gouges or paint chips in the filler tube's sealing area.
A purge valve that no longer seals
The purge valve sits between the canister and the engine and should stay shut until the computer opens it. Advance says it fails after 60,000 to 80,000 miles on the Jeep Grand Cherokee's 3.6-liter Pentastar V6. It names the 2011 to 2021 Grand Cherokee and 2012 to 2018 Wrangler JK as the highest-volume P0456 Jeeps, and on the Wrangler it says to start with the gas cap.
Ford's summary maps a leaking purge valve to P1450 or P0496, yet Ford bulletin 16-0075 pairs it with P0456 too. It covers a hard start, no start or rpm loss after refueling, sometimes with P1450 and/or P0456, fixed with a new purge valve.
A valve stuck open also lets air into the intake, and our guide to the P0171 system too lean code lists it among the unmetered air leaks behind a lean code.
A vent valve or canister close valve seal
The vent valve, which Kia calls a canister close valve, must close tightly to seal the system for the test.
Nissan's bulletin NTB17-082E covers 2008 and newer Nissans, except the LEAF and Titan XD diesel, with a P0456 not caused by a loose cap. It blames the vent control valve O-ring and replaces the valve as an assembly, since the O-ring is no longer sold separately.
Kia's bulletin FUE040 ties P0455 and P0456 on 2012 to 2017 Rios to a stuck-open canister close valve, replaced with one that uses a new rubber seal material.
Cracked hoses and loose connections
Advance ranks a cracked or disconnected hose second, and on EcoBoost Escapes it points to the hoses near the turbo and intercooler piping.
FCA's bulletin 25-002-15 Rev. B traced P0455 and P0456 on some 2015 Jeep Grand Cherokee and Dodge Durango models to a split purge valve vapor hose.
Some joints hide behind trim. Volkswagen's Atlas tech tip 01-19-09TT checks the hose connections on top of the tank with soapy water and names those behind the fuel filler door's rubber boot as a common leak.
A cracked charcoal canister
Advance says canisters crack from road debris or saturate from repeated overfilling. Hyundai's canister bulletin 17-FL-002 found potential cracks at the insert nuts on 2012 to 2016 Velosters and 2011 to 2015 Sonata Hybrids, and extended canister coverage to 10 years or 120,000 miles. That extension excludes cars in 27 salt-belt states and the District of Columbia, and it points cars with an open Campaign 948 to a separate bulletin, so ask a Hyundai dealer which one covers your VIN.
Leak detection parts, software and the tank
Some P0456 codes come from the testing parts. Hyundai's bulletin 20-FL-003H says salt deposits can form inside the natural vacuum leak detection (NVLD) sensor on 2016 to 2019 Sonata Hybrids, fixed with a new sensor and an updated air filter kit.
At the tank end, CarParts.com says a damaged tank or a fuel pump sealed improperly after tank removal can cause small leaks.
How to Diagnose P0456 With a Scanner
Rule out the cap, let the car rerun its test, then check the valves and smoke test the system. Freeze frame data and pending codes help, as our roundup of the best OBD2 scanners explains.
- Read every code, including pending ones. Advance says P0441 points to the purge valve and P0446 to the vent valve.
- Check for a bulletin. Several P0456 fixes are software updates or model-specific parts.
- Inspect the cap and filler neck. Look for a cracked or flattened O-ring and nicks in the sealing surface, then tighten the cap until it clicks.
- Clear the code and drive normally. Advance suggests two to three complete drive cycles, and NYVIP3 says to keep the tank a quarter to three-quarters full.
- Inspect every hose you can reach. Work from the purge valve back to the canister and tank.
- Command the purge and vent valves. GM says cycling both with a scan tool while inspecting may reveal a sticking valve.
- Vacuum-test the purge valve. Mitsubishi uses a hand pump to confirm the valve holds vacuum.
- Smoke test with the original cap in place. AutoZone says to close the vent solenoid with the scan tool first.
- Test the tank on its own if the smoke shows nothing.
- Fix, clear and run the carmaker's leak test. Toyota uses an Evaporative System Check in Techstream and Hyundai a GDS Evap Leakage Test to confirm a repair.
The Smoke Test Problem: When Shops Can't Find the Leak
A smoke machine is the standard tool for P0456, but a very small leak can still slip past it. AutoZone also warns against pressurizing the system with air, which could damage the vent solenoid and purge valve.
FCA's STAR case on P0456 and P0455 says its smoke tool's adapter, used in place of the gas cap, could mask the leak, so technicians leave the original cap on.
Mazda's EVAP leak bulletin 01-002/18 adds an ultrasonic leak detector at the filler cap during an EVAP test and sets the smoke tester's gauge to 13 to 15 inches of water.
In a TechShop magazine case study, a 2003 Dodge Caravan with P0456 showed no visible smoke, but a flow meter confirmed a leak, and testing the tank alone found it there, from a poor earlier repair.
The leak can even sit inside a test part. Audi's Q7 bulletin 2035519/4 pressurizes the system to 12 inches of water, and if it still holds at least 9 inches after 3 minutes, technicians replace the leak detection pump.
When there may be no leak at all
Subaru's P0456 reprogramming bulletin says the update should be installed only after confirming an actual leak does not exist. If the cap, hoses and smoke test all pass, ask the shop to check for a software bulletin.
Carmaker Bulletins for P0456: Toyota, Acura, Subaru, Ford and Others
Check for a bulletin before you buy parts. Each one below was filed with NHTSA and applies only to listed models, build dates or VINs.
| Vehicles | Bulletin | What it found | Fix |
|---|---|---|---|
| 2014 to 2016 Toyota Corolla built at TMMMS before a set VIN | Toyota T-SB-0086-16 | Filler neck out of position | Reposition the filler neck |
| 2011 to 2013 Acura ILX, MDX, RDX, TL, TSX and ZDX in listed VINs | Acura 14-006 | Cap gasket friction | New cap with a brown gasket |
| 2013 to 2015 Acura RDX | Acura 14-053 | PCM may misread EVAP inputs on short drives | Leak check, then PCM update |
| 2011 and 2012 Subaru Legacy and Outback, 2012 Forester Turbo and Tribeca | Subaru 11-126-12 | P0456 with no drivability concern | ECM reprogramming once no leak is confirmed |
| 2013 Ford Escape, 2013 to 2014 Fusion and Lincoln MKZ built through November 9, 2013 | Ford 16-0075 | Hard start after refueling | New purge valve |
| 2013 to 2017 Ford C-MAX, Fusion and Lincoln MKZ Hybrid and Energi | Ford 19-2207 | Purge valve sealing | PCM reprogram and new purge valve |
| 2008 and newer Nissan, except LEAF and Titan XD diesel | Nissan NTB17-082E | Vent control valve O-ring | New vent control valve |
From Toyota, American Honda (Acura), Subaru, Ford and Nissan bulletins filed with NHTSA. The 2011 Subaru models are later production only. Confirm with a dealer that your VIN is covered.
Toyota's bulletin T-SB-0086-16 moves the filler neck opening further outside the body, then confirms the cap clicks or springs back. Toyota covers it under its emission warranty of 36 months or 36,000 miles, or 36 months or 50,000 miles in California emission states.
Toyota owners may see P0442 instead, since Advance says it is more common than P0456 on Camry, RAV4 and Corolla models.
Acura bulletin 14-053 applies only when the drive before the fault lasted under 20 minutes and the car passes Honda's EVAP function and vacuum tests.
Subaru's bulletin 11-126-12 notes that the customer may have tightened the cap or refueled after the light came on, which can seat the cap properly.
Ford's hybrid bulletin 19-2207 blames the sealing capability of the canister purge valve on the 2013 to 2017 hybrids and Energi plug-ins.
Is It Safe to Drive With P0456?
Yes, in most cases. RepairPal's P0456 page rates it "Moderate," a code that may not affect safety or function right away but should be diagnosed within a reasonable time.
OBDeleven's P0456 page adds two cautions: prolonged exposure to fuel vapor may cause headaches and respiratory issues, and a lit light can hide a new engine fault.
| Situation | Severity | What to do |
|---|---|---|
| Steady light, normal running, no fuel smell | Moderate | Check the cap, then get it diagnosed soon |
| Strong smell of raw fuel | High | Park outdoors and have it checked right away |
| Hard start or rpm drop after refueling | Act soon | Have the purge valve checked |
| Flashing light or rough running | Not from P0456 alone | Read every code and get prompt service |
From RepairPal, Advance Auto Parts, OBDeleven and Ford bulletin 16-0075.
A strong gas smell is not a small leak
P0456 leaks are tiny, so a strong smell of raw gasoline points to something more. OBDeleven warns that a cracked fuel tank can leak fuel vapor and cause a fire. Keep the car out of closed garages and have it inspected before driving far.
Free tool
Check Engine Light Checker. Say whether the light is steady, flashing or came on and went off, and tick a recent fill-up, rough running or a red warning light, to get a Low risk, Act soon or Stop and check ruling.
Because it reads the light and your symptoms rather than the code, the Check Engine Light Checker works best alongside a scan.
How to Fix P0456 and What It Costs
Most P0456 parts are cheap; the time goes into finding the leak. RepairPal's emission system diagnosis estimate puts shop testing at $61 to $90.
| Repair | RepairPal estimate | Advance shop estimate | Advance DIY part |
|---|---|---|---|
| Gas cap | $138 to $150 | $5 to $15 | $5 to $15 |
| Smoke test | Not listed | $60 to $150 | $0 to borrow or rent |
| EVAP hose | Not listed | $75 to $200 | $5 to $20 |
| Purge valve | $210 to $251 | $100 to $250 | $15 to $50 |
| Vent valve | Not listed | $100 to $250 | $20 to $60 |
| Fuel tank pressure sensor | $356 to $457 | $150 to $350 | $30 to $80 |
| Charcoal canister | $558 to $643 | $200 to $400 | $50 to $150 |
RepairPal national estimates for parts and labor, updated September 3, 2026, before taxes and fees. Advance Auto Parts figures from its P0456 guide, updated September 11, 2026, except the smoke test and pressure sensor, from its P0455 guide.
The gas cap gap is large because RepairPal assumes a part around $114 plus labor, and notes that some vehicles need a dealer cap because a poorly matched cap cannot seal.
RepairPal's purge valve estimate splits its total into $65 to $95 of labor and $146 to $156 of parts.
The 2026 CarMD Vehicle Health Index ranks EVAP purge valve replacement sixth among 2025 check engine repairs, averaging $172.12.
RepairPal's canister estimate adds that topping off the tank can fill the charcoal canister with fuel and cause system failure.
Free tool
Repair Cost Estimator. Enter a shop's parts price, labor hours, labor rate, diagnostic fee and other fees to see the total and the parts-only DIY cost, then pick "EVAP purge control valve" to compare a purge valve quote with its $172 national average.
When a long leak hunt is billed by the hour, the Repair Cost Estimator also shows the total at $100 and $200 an hour.
On a newer car, ask about coverage first. Federal emission warranty rules give cars and light trucks a two-year or 24,000-mile emission defect warranty, though EVAP valves and canisters are not on the eight-year or 80,000-mile list of major parts.
After the Repair: Permanent Codes and Smog Checks
Clear the code only after the fix, then let the car rerun its test. EPA's 1995 OBD rule lets the light go out once the fault doesn't recur during three sequential trips in which the monitor runs without detecting it.
California is stricter. The Bureau of Automotive Repair's permanent code article says permanent codes have counted at Smog Check on 2010 and newer vehicles since July 1, 2019, and it lists P0442 and P0456 as the top permanent code for gasoline and flex-fuel vehicles.
A scan tool or a battery disconnect can't clear a permanent code. It clears only when the monitor runs and finds no problem, and BAR ignores one only after 15 warm-up cycles and 200 miles since the codes were last cleared. In the first month, July 2019, BAR says 3,124 vehicles failed for permanent codes that would previously have passed.
Codes Related to P0456
P0456 often arrives with other EVAP codes, and some point straight at a part.
| Code | Meaning | What it tells you |
|---|---|---|
| P0455 | EVAP large leak | No test vacuum at all on Ford |
| P0442 | EVAP small leak | A 0.040-inch leak on Ford; a stuck-open purge or vent valve on GM |
| P0457 | EVAP leak, fuel cap loose or off | Cap left loose after a fill-up |
| P0441 | EVAP incorrect purge flow | Points to the purge valve |
| P0446 | EVAP vent control circuit | Points to the vent valve |
| P0496 | EVAP high purge flow | With P1450, a leaking purge valve on Ford |
From Ford's 2019 OBD System Operation Summary, GM bulletin 21-NA-124, Advance Auto Parts and Volkswagen tech tip 01-19-09TT.
Frequently Asked Questions
Will P0456 go away on its own?
Only if the leak goes away. RepairPal says most codes clear themselves once the system no longer detects the problem, and EPA rules let the light go out after three trips in a row in which the monitor runs without finding it. A cap that was simply loose can reseat after a fill-up, but a cracked seal or leaking valve will set the code again.
Can you fix a P0456 leak yourself?
Often, if you can find it. Advance Auto Parts lists DIY parts at $5 to $15 for a gas cap, $5 to $20 for an EVAP hose and $15 to $50 for a purge valve, and says a smoke machine can be borrowed or rented. Locating a very small leak is the hard part, which is why many owners pay a shop $60 to $150 for a smoke test.
What does P0456 mean on a Ford Escape?
It means the same very small EVAP leak. Advance Auto Parts says 2013 to 2019 Escapes commonly trigger P0456 and suggests checking the hoses near the turbo and intercooler piping on EcoBoost engines. Ford bulletin 16-0075 also covers some 2013 Escapes built through November 9, 2013 that start hard after refueling, which it fixes with a new purge valve.
Does P0456 hurt gas mileage?
Usually not in a way you would notice. Advance Auto Parts says P0456 causes no change in engine performance, while AutoZone says slightly lower fuel economy may appear over time. The bigger cost is environmental, since EPA has noted that emissions from leaking gas caps below the 0.020-inch threshold may still be significant.
How long does it take P0456 to come back after clearing it?
It depends on when the car can run its leak test. Ford's engine-off test runs at most twice a day and needs the right fuel level, temperature and soak time, though its first four tests after a code clear use unfiltered data to flag a fault quickly. NYVIP3 says the light comes on once the fault appears on two drive cycles.
Can a new gas cap fix P0456?
Often, if the old cap or its seal was the leak. Advance Auto Parts suggests starting with a new cap before paying for other diagnosis, and Acura's bulletin 14-006 replaced caps whose gaskets created too much friction to seal. RepairPal warns that some vehicles need a dealer cap, because a poorly matched cap can work but still fail to seal the system.
Sources and References
- Ford Motor Company. 2019 MY OBD System Operation Summary for Gasoline Engines
- Advance Auto Parts. P0456: EVAP System Small Leak Detected
- Advance Auto Parts. P0455: EVAP System Large Leak Detected
- U.S. EPA. Effectiveness of OBD II Evaporative Emission Monitors: 30 Vehicle Study (EPA420-R-00-012)
- California Air Resources Board. Attachment IV: Proposed Modifications to Malfunction and Diagnostic System Requirements (OBD II), Section 1968.2
- Mitsubishi Motors. DTC P0456: Evaporative Emission System Leak Detected (Very Small Leak)
- New York Vehicle Inspection Program (NYVIP3). EVAP System Monitor
- CarParts.com. P0456 Code: EVAP System Small Leak: Meaning, Causes, Symptoms, and Fixes
- General Motors (via NHTSA). Bulletin 21-NA-124: Diagnostic Tip for Malfunction Indicator Lamp (MIL) Illuminated, DTC P0442 and/or P0455 Set
- O'Reilly Auto Parts. Check Engine Light Code P0456: Evaporative Emission System Leak Detected
- AutoZone. P0456: Evaporative Emissions System, Small Leak Detected
- RepairPal. Gas Cap Replacement Cost Estimate
- American Honda (Acura, via NHTSA). Service Bulletin 14-006: MIL Comes On With DTC P0455 and/or P0456
- Ford Motor Company (via NHTSA). TSB 16-0075: Hard Start/No Start/Loss of Engine RPM After Refueling, Built On or Before 11/9/2013
- Nissan (via NHTSA). NTB17-082E: DTC P0456 Caused by EVAP Leak at Vent Control Valve O-ring
- Kia (via NHTSA). TSB FUE040: Canister Close Valve (CCV) Replacement
- FCA US (via NHTSA). Service Bulletin 25-002-15 Rev. B: P0455/P0456 Set in the Powertrain Control Module (PCM)
- Volkswagen Group of America (via NHTSA). Tech Tip 01-19-09TT: EVAP Fault(s) P0442, P0456, P0441, P0496 Present After Software Update
- Hyundai (via NHTSA). TSB 17-FL-002: Canister Inspection and Repair (Warranty Extension TXX9)
- Hyundai (via NHTSA). TSB 20-FL-003H: DTC P0456: EVAP System, Very Small Leak
- FCA US (via NHTSA). STAR Online Publication S2025000004: Customer Complains of the MIL Lamp On (P0456/P0455)
- Mazda North American Operations (via NHTSA). TSB 01-002/18: Determining Evaporative System Leak Location for DTCs P0441/P0442/P0455/P0456
- TechShop Magazine. Pulling Codes: The Story of Code P0456
- Audi of America (via NHTSA). TSB 2035519/4: MIL On (DTC P0456 or DTC P0442 (EVAP Emission Control System Leak Detected))
- Toyota Motor Sales, USA (via NHTSA). T-SB-0086-16: Gas Cap No Click and/or No Spring Return
- American Honda (Acura, via NHTSA). Service Bulletin 14-053: TIGHTEN FUEL CAP Message On or DTC P0455 and/or P0456 Is Set
- Subaru of America (via NHTSA). Bulletin 11-126-12: DTC P0456 Reprogramming File Availability
- Ford Motor Company (via NHTSA). TSB 19-2207: Hybrid/Energi, Illuminated MIL With DTCs P1450, P0456, P0457, P04EE and/or P04EF
- RepairPal. P0456 OBD-II: Evaporative Emission System Leak Detected (Very Small Leak)
- OBDeleven. P0456: Evaporative Emission Control System Very Small Leak Detected
- RepairPal. Emission System Diagnosis & Testing Cost Estimate
- RepairPal. Purge Valve Replacement Cost Estimate
- RepairPal. Fuel Evaporative Canister Replacement Cost Estimate
- RepairPal. Fuel Tank Pressure Sensor Replacement Cost Estimate
- CarMD. 2026 CarMD Vehicle Health Index
- eCFR (Office of the Federal Register). 40 CFR 85.2103: Emission Warranty
- U.S. EPA (Federal Register). Regulations Requiring On-Board Diagnostic Systems: Revision to Requirements for Storage of Engine Conditions Associated With Extinguishing a Malfunction Indicator Light (August 2, 1995)
- California Bureau of Automotive Repair. Permanent Diagnostic Trouble Codes (Automotive Repair and Smog Check News, Fall 2019)
Written by
CarTipsMentor Team
Researched from the sources listed above and checked against them before publishing. Nobody paid to be mentioned on this page. It is general information, not advice about your own vehicle.
Published . Last updated .
