P0455 Code in 2026: $0 to $1,500, the Gas Cap First, and What Manufacturers Check Next

P0455 is a failed leak test, not a failed part. The engine computer seals the fuel vapour system, tries to hold a small vacuum or pressure in it, and when it cannot hold it at all, it sets a "large leak" code.

The first thing manufacturers tell their own technicians to check is free. Nissan's bulletin for every 2012 and newer car, NTB13-097J, starts its flow chart with "Confirm the fuel filler cap is secure," and if the system then passes a pressure test, the instruction is blunt: "DO NOT REPLACE FUEL FILLER CAP OR ANY OTHER EVAP RELATED PARTS." Ford went further in a 2021 message to dealers: it "has tested returned EVAP canister purge valves and found them to be fully functional."

By the end of this guide you will know which of five routes your P0455 belongs to, what proves it, and what each one costs, from a $0 cap check to a $1,500 job inside the fuel tank. Claims marked 🟢 rest on a document in Sources, opened and read; ⚪ marks estimates and owner reports.

I built Pulscar, an AI tool that identifies car problems from a 30-second recording, after spending $6,000 on misdiagnosed repairs, starting with a $380 bill for a noise three people had called serious, which turned out to be a $5 heat shield.

How to use this guide

Every route is defined by when the light came on and what the car did around refuelling, not by the code itself.

One rule overrides everything: prove where the leak is before you buy a part. The system is a sealed loop of cap, filler neck, tank, hoses, canister and two valves, and the code cannot tell them apart.

First: is this really P0455? The EVAP codes side by side

Write down every code stored with it. The neighbours change the route.

The tighter codes are about hole size. California's OBD rule, 13 CCR 1968.2, requires monitors to detect leaks as small as a 0.040-inch and a 0.020-inch hole. P0455 means the system failed before any fine measurement was possible, which is why it is so often something open rather than cracked.

A large leak can be a blockage. GM's bulletin 21-NA-124 says a vehicle "will set the code due to large leak or purge blockage."

A cap message is not a code. Acura's bulletin 11-012 for the 2012 TL describes a "TIGHTEN FUEL CAP" message with no P0455 stored, fixed with software.

Why the light came on, and when it goes out by itself

The evaporative system stores fuel vapour from the tank in a charcoal canister. A purge valve lets the running engine draw that vapour in to burn it; a vent valve lets fresh air into the canister and closes when the computer tests the system.

The test. Kia's PITSTOP procedure PS469 shows the logic: close the vent valve, pull a partial vacuum with the purge valve, and watch the tank pressure sensor, whose voltage "should not change more then .300v in one (1) minute." If the vacuum will not build at all, you get P0455.

Why it appears days after a fill-up. Nissan: "If a fuel filler cap is left loose for multiple trips, DTCs will be stored and the MIL will illuminate."

When it goes out on its own. 13 CCR 1968.2 requires the light to go out "after three subsequent sequential driving cycles" in which the monitor runs and the fault is gone, and the code to be erased after 40 warm-up cycles. The EVAP test needs particular conditions, so that is often several days of driving ⚪. Nissan adds that "Test driving the vehicle for these DTCs will only waste time."

The 10-minute driveway protocol

1. Read the codes and save them before anyone clears them. A $20 to $40 reader shows whether P0441, P0446 or P0456 sits beside P0455.
2. Walk around the car and smell. Liquid petrol, a wet spot or drips is a fuel leak: stop and read the gas smell guide. A faint vapour smell over dry ground is EVAP territory.
3. Take the cap off and look at it. Grit on the sealing surface, a cracked rubber ring, a tether trapped under the seal.
4. Refit it until it clicks. Ford's instruction: clockwise until at least one audible click. A Corolla cap that never clicks is a documented filler neck fault.
5. On a capless filler, check the flap closes. Acura blames a flap stuck open on the 2021 TLX.
6. Write down how the last fill-up went. A nozzle clicking off, a tank that stops at half, a stall afterwards: each is a different route.
7. Run the VIN through NHTSA's recall lookup and the manufacturer's owner site.

Ten minutes and a cheap reader do the first half of what a diagnostic fee buys; what a diagnostic should cost covers the rest.

Find your situation: eight ways people arrive here

"The light came on days after I filled up." → Route 1. The classic loose or dirty cap.

"My cap never clicks, or I have a capless filler." → Route 1, then Route 2.

"The pump keeps clicking off, or the tank stops at half." → Route 2.

"I smell fuel near a rear wheel, but nothing drips." → Route 2.

"It stalls or idles rough right after a fill-up." → Route 3, and on a Focus, a recall.

"New cap, new purge valve, and the light is back." → Route 4.

"I failed inspection with P0455." → The inspection section, then your route.

"Salt-belt Kia Optima or Sedona, or Hyundai Veloster." → Route 5.

What actually determines your number

Where the leak is. A cap is seconds away; a vapour line inside the tank took Ford 4.9 hours on the 2024 Edge.

Tested or guessed. Nissan charges dealers back for EVAP parts returned in working order. A tested repair is one part; a guessed one is three.

Access. Ford's Maverick canister line job includes lowering the tank, 2.1 to 2.7 hours.

Your VIN. Kia's SC135 applies by build date and by state.

The warranty clock. For EVAP parts the federal minimum is 2 years or 24,000 miles, not the 8-year converter term.

How you drive. Dust and road salt appear in bulletins as causes, and GM bills its dust fix to the owner.

The price ladder: read it from the bottom up

Read it from the bottom up: the last line and several expensive lines above it are the same parts, separated by a VIN, a date and a test.

Your number, by what you drive

Which route is yours? Five questions

1. Did the light appear within days of a fill-up, with a normal-running car and no other EVAP code? → Route 1. The cap and its seal.

2. Is refuelling itself hard, or is there a fuel vapour smell near the filler or a rear wheel? → Route 2. Filler neck, vent path and canister.

3. Does the car stall, restart hard or idle roughly right after refuelling, or is P0441 stored too? → Route 3. The purge valve.

4. Has the cap already been replaced and the light returned? → Route 4. Hoses, connections and a proper leak test.

5. Is your VIN on a recall, campaign or extension? → Route 5. Run this one first, whatever else you answered.

The five routes, cheapest first

Route 1 · The light came on after a fill-up — the cap and its seal

The tell. A steady light days after refuelling, a car that drives normally, P0455 alone or with P0456 or P0457.

What it actually is. The cap is the biggest opening in the system, and it is opened by hand every week. Nissan's NTB09-020F for 2007-2011 models says "a loose fuel fill cap may be the cause." Its successor NTB13-097J, February 2022, covers all 2012 and newer Nissans; Infiniti's ITB09-012F and ITB13-044J are the twins. The technician pressurises the system for 10 minutes; if it holds, the verdict is "MIL ON due to fuel filler cap not being properly secured," the code is erased and nothing is replaced.

When the cap is fine but will not seal. Ford's SSM 51719, for 2021-2023 F-Super Duty and E-Series petrol trucks, blames "improper fuel filler cap installation and/or outside contamination on the fuel cap sealing surface." Toyota's T-SB-0086-16 covers 2014-2016 Corollas built at the TMMMS plant, VIN starting 5YF, whose cap gives "No Click" because the filler neck sits out of position: 0.8 hours to reposition it. GM's PI0873 found a cap tether binding under the seal on 2012-2013 Express and Savana cutaway vans.

When the cap itself was the defect. Stellantis 14-005-22 REV. B fits an updated cap to 2021 Wrangler, Gladiator, Challenger, Ram and ProMaster models built 1 June to 6 October 2021, and still requires normal diagnosis afterwards.

The cheap cause that gets skipped. Grit on the sealing ring. A cap that clicks but sits on sand leaks exactly like a loose one, and Ford's own fix starts with cleaning it.

Fix it yourself — the cap, properly. Wipe the rubber ring and the filler lip, look for cracks, flat spots or a trapped tether, refit and turn until it clicks. If the ring is damaged, buy a cap by the manufacturer's part number. Then drive normally for a week. The honest limit: if the light is still on after a week, or returns, the cap was not the answer; go to Route 4 rather than buying a second cap.

Where this does not apply. A strong fuel smell, stalling after refuelling, or a pump that keeps clicking off are not cap symptoms: Routes 2 and 3.

At the shop — say this: "P0455, and I have already cleaned and refitted the cap. Before replacing anything, please run a leak test with the cap in place and tell me whether the system holds. If it holds, I would like the code cleared and no parts fitted."

Route 2 · Hard to fill, or a vapour smell at the back — filler neck, vent path and canister

The tell. The nozzle clicks off every few seconds, the tank fills slowly or stops short, or there is a vapour smell near the filler or a rear wheel. P0446 or P0449 may sit beside P0455.

What it actually is. While you refuel, displaced vapour must flow through the canister and out of the vent. Block that path and the tank cannot breathe; open it where it should be closed and the leak test fails. GM's 15-06-04-002, April 2015, for 2011-2015 Silverado and Sierra pickups, describes owners who say "The fuel tank is hard to fill," with dust or water in the canister vent valve, and warns: "DO NOT replace the EVAP canister assembly for this concern unless it fails the leak test."

Dust and spiders. GM's 23-NA-073, March 2025, covers 2019-2025 Silverado and Sierra 1500 and 2020-2025 HD trucks used "in extremely dusty environments": an inline vent filter, and "a customer pay alteration." Isuzu's SB19-J-002 relocates the vent valve on 2012-2019 N-Series 6.0L trucks used for "farming, sweeping, or off-road" work. GM's 17-NA-383 tells technicians on 2013-2017 Encore, 2012-2017 Sonic and 2013-2017 Trax models with P0446 or P0455 to "Inspect the evaporator canister for spider nesting in the fresh air inlet port," then replace the canister.

Capless fillers, and the smell. Honda's tech line article ATS 170206 for the 2016 Pilot and 2017 Ridgeline: "don't replace the fuel fill pipe!" Replace the flap parts instead. Acura's 21-007 for the TLX found "The fuel main flap unit may have stuck open." Stellantis 18-035-20 pairs P0455 on some 2020 Grand Cherokee and Durango 3.6L models with "Fuel odor smell in the left rear wheel opening," from a vapour hose never connected. Kia's FUE033 changes a fill level valve inside 2014-2015 Sorento tanks: "Replacement of fuel tank is not necessary."

The cheap cause that gets skipped. The vent inlet, often a small filter near the filler or above the rear axle, where mud, dust or webs are visible without removing anything.

Fix it yourself — look at the vent side. Car cold and on level ground, trace the hoses from the filler neck toward the canister with a torch. Look for packed dust, webs, a crushed hose or a line hanging loose, and check that a capless flap closes. The honest limit: never work under a car on a jack alone, never pull fuel lines, and anything that needs the tank lowered is a shop job.

Where this does not apply. A tank that fills normally on a car that stalls afterwards is Route 3. If the nozzle clicks off at one station only, try another pump first.

At the shop — say this: "P0455 and the tank is hard to fill. Please check the vent path and canister inlet for dust, water or blockage before replacing the canister, and look for any bulletin on this VIN for the vent valve or filler neck."

Route 3 · Stalls or idles rough right after refuelling — the purge valve

The tell. The engine stalls or will not restart for a minute after refuelling, then runs. A loping, uneven idle that settles after a few minutes. P0441 or P0496 stored beside P0455 or P0456; on several Fords in these documents, P1450 as well.

What it actually is. The purge valve sits between the canister and the intake. Stuck open, it lets the engine suck vapour, and even liquid fuel, from the tank whenever it runs, which is worst when the tank has just been filled. Stuck closed, the computer cannot draw its test vacuum at all, and GM's 21-NA-124 lists "a stuck closed purge valve" among the causes of P0455.

The recall. NHTSA campaign 18V-735, reported by Ford on 22 October 2018, covers 1,282,596 2012-2018 Focus cars with the 2.0L GDI or GTDI engine. The purge valve "may malfunction, possibly causing excessive vacuum in fuel vapor management system," and the consequence is a stall "without warning and without the ability to restart the vehicle." Dealers reprogram the engine computer, check for fault codes and replace the valve as needed; if they do, they inspect and replace the canister, fuel tank and fuel delivery module as necessary. Ford's number is 18S32, the recall began on 19 August 2019, and until repair owners are advised "to keep the fuel tank at least halfway full."

Two more Fords. SSM 46525 covers 2017 Escape and MKC vehicles with P0455 or P0456 and "rough idle and/or slow fuel fill"; if the purge valve is replaced, "Liquid fuel should not be present" in the lines or canister. Bulletin 25-2431, September 2025, superseding 24-2199, covers the 2024 Edge AWD 2.0L that "Stalls upon restart after refueling": a vapour line loose inside the tank, 4.9 hours with a new canister.

The cheap cause that gets skipped. The hose, and the test. Stellantis 25-002-15 replaced a split purge hose on 2015 Grand Cherokee and Durango models built 16 November 2014 to 17 January 2015, 0.3 hours. Ford's SSM 50306 told dealers across 2018-2022 models to run the full leak test and the purge valve test before replacing "the canister purge valve or other EVAP components." Kia's tip TT051 for the 2012 Sorento starts the same way: "Test the functionality of the PSV."

Where this does not apply. A car that stalls or will not start at random, with no link to refuelling, belongs in the cranks but won't start guide or the rough running guide. A Focus not listed under 18V-735 can still have a failed purge valve; it just is not free.

At the shop — say this: "P0455 and the car stalls after refuelling. Please check this VIN for 18V-735 and any purge valve bulletin, and run a purge valve leak test before replacing it. If you replace it, check the canister and lines for liquid fuel and tell me what you found."

How can you tell a purge valve stuck open from a loose gas cap without a scan tool? By when the engine misbehaves, and by how it sounds. A loose cap is silent: the car drives normally and the light simply appears a few trips later. A purge valve stuck open behaves like a hole between the fuel tank and the intake, so it shows itself right after a fill-up, when the tank is full of fresh vapour. One 2016 Focus owner told NHTSA the car stalled after refuelling and the engine "rumbles excessively for a couple minutes." That uneven, loping idle is a sound, and it fades as the vapour burns off. Record 30 seconds of idle straight after your next fill-up, and Pulscar's AI compares it against catalogued failure patterns, then returns the likely cause, whether it is safe to drive, and the fair 2026 price. Free, no card, no subscription, about ten minutes. The report arrives by email.

Route 4 · A new cap and the light came back — connections, hoses and a real leak test

The tell. The cap has been cleaned or replaced, the light went out or never did, and P0455 is back within days or weeks. The car drives normally.

What it actually is. Somewhere a joint is open. GM's 21-NA-124, revised December 2022 for every GM petrol engine from 2000 to 2023, lists "seven critical connections," from the purge tube at the intake manifold to the fuel cap, and a fixed order: lines seated, lines undamaged, then the vent valve, then the purge valve. "Some leaks will only be noticeable under pressure and some only noticeable under vacuum. We recommend checking both ways."

Documented loose lines. Ford's 16-0132: 2017 Escape 1.5L models built on or before 9 June 2016, an underhood vapour line "disconnected or loose," 0.3 hours. Ford's 25-2308: 2022-2024 Mavericks, a canister line chafing on the vent hose. Ford's SSM 49313: 2020 Escape and Corsair canisters damaged in transport, a fault that "may not occur for a few hundred miles."

When the leak hides from the test. Mazda's 01-002/18, for 2004-2010 Mazda3, 2003-2010 Mazda6, 2006-2015 MX-5 and other models, says "DO NOT TOUCH the fuel filler cap" while diagnosing, and warns that with smoke fed through the filler neck adapter, "leakage from the fuel filler cap will not be detected." Kia's PS469 is for the car whose self-test finds nothing: a manual vacuum test, then pinching off hoses one branch at a time. On the 2011-2015 Sonata Hybrid, Hyundai's 21-FL-002H found salt inside the leak detection sensor itself.

The cheap cause that gets skipped. A connector never clicked home after nearby work. A 2018 HR-V owner told NHTSA that after fuel pump recall work, a smoke test found the leak at the pump area; the bill was $1,676.61.

Fix it yourself — walk GM's list with a torch. Engine off and cool, follow the purge line from the intake manifold toward the firewall and check every quick connector is seated and the hose uncracked. Under the rear, look for a damaged underbody panel near the canister or a line hanging free. The honest limit: you cannot safely pressure-test a vapour system at home, and a leak on top of the tank is invisible without lowering it; that is what a $50 to $150 smoke test buys.

Where this does not apply. If P0441 or P0446 is stored too, the valves are in play: Routes 3 and 2. If a strong fuel smell appeared with the code, rule out a liquid leak first.

At the shop — say this: "P0455 has come back after a new cap. Please smoke test the EVAP system under both pressure and vacuum, tell me where the smoke was introduced, check the cap separately, and show me a photo of the leak before replacing any valve or canister."

Which P0455 repairs does a manufacturer pay for, and which are yours? It depends on a document, a date and sometimes a state, not on the code. A 2012-2018 Focus 2.0L inside recall 18V-735 gets its purge valve, and if needed its canister and fuel tank, at no charge. A salt-belt Optima, Rondo or Sedona inside Kia's SC135 build windows gets a canister inspection, and elsewhere Kia extended canister cover to 10 years or 120,000 miles from first service. A certain 2012-2016 Veloster or 2011-2015 Sonata Hybrid in a salt-belt state falls under Hyundai's campaign 948. Outside those lists, federal law gives most EVAP parts a 2-year, 24,000-mile emissions warranty, and California requires 3 years or 50,000 miles. Against that, GM's dust filter for Silverado and Sierra trucks is customer-paid by design. Pulscar tells you whether your idle sounds like a valve fault before the question of who pays comes up.

Route 5 · Your VIN is on a document — recalls, campaigns and the warranty clock

The tell. Your car is in the table above, a letter arrived, or a dealer mentioned a campaign.

What it actually is: Kia's salt-belt canister. Kia's voluntary emissions service campaign SC135, revision 1 of 13 October 2016, covers Optima built 2 September 2010 to 29 November 2014, Optima Hybrid built 15 February 2011 to 29 November 2014, Rondo built 1 April 2009 to 30 July 2010 and Sedona built 1 April 2009 to 17 June 2014. In 28 salt-belt jurisdictions the dealer inspects the canister: no crack means a new bracket, a crack means a new canister. "For vehicles in other states, Kia is extending the warranty on the evaporative canister from 5 years/60,000 miles to 10 years/120,000 miles." In 13 states a completion card is needed at registration renewal.

The date arithmetic. The extension runs from first service and production ended in November 2014, so in September 2026 only a car first put into service after September 2016 can still be inside it. Ask whether the salt-belt inspection is still open on your VIN.

Hyundai's version, and a Rio valve. Hyundai's campaign 948, bulletin 17-01-003-1 of January 2017, inspects canisters on certain 2012-2016 Veloster and 2011-2015 Sonata Hybrid vehicles in salt-belt states. Kia's bulletin FUE040 replaces a canister close valve "stuck open" on 2012-2017 Rios built 21 June 2011 to 28 March 2016, 0.4 hours; as a bulletin, your warranty decides who pays.

The cheap cause that gets skipped. The clock. Federal law, 42 U.S.C. 7541(i)(1), sets the emissions warranty period at "the first 2 years or 24,000 miles of use" for 1995 and newer light-duty vehicles. The 8-year, 80,000-mile term in 7541(i)(2) is for a "specified major emission control component," which the statute limits to the catalytic converter, the electronic emissions control unit and the onboard diagnostic device, so a canister or purge valve does not get it. California's 13 CCR 2037 requires 3 years or 50,000 miles on warranted parts and 7 years or 70,000 miles on high-priced ones. Manufacturers may give more: Toyota's Corolla filler neck bulletin was covered under its federal emission warranty of "36 months or 36,000 miles."

Where this does not apply. Customer-pay bulletins stay customer-pay, like GM's 23-NA-073 dust filter, and GM's PI0873 tether fix was billed to the van's upfitter. Several Focus owners in the complaint file had the 18V-735 symptoms and a VIN the recall did not list.

At the shop — say this: "Run this VIN for every recall, emission campaign and warranty extension, open or completed, and tell me the in-service date. If an EVAP part fails inside the emissions warranty, please claim it there before quoting me."

What does it actually cost to fix a P0455 code in 2026? It depends on which part of a sealed system is open. At the bottom: a cleaned and refitted cap for nothing, a replacement cap at $10 to $25 as a part, a code read at $0 to $40. In the middle: a smoke test at $50 to $150, a diagnostic fee of $80 to $150 at an independent shop or $120 to $200 at a dealer, a loose or split hose at $15 to $150, a purge valve at $150 to $300 installed and a vent valve at $150 to $350. At the top: a filler neck at $200 to $500, a charcoal canister at $200 to $650, and work inside the fuel tank at $400 to $1,500, where Ford's Edge bulletin allows 4.9 hours. The same parts cost $0 inside 18V-735, SC135 or a live emissions warranty. Pulscar prices your recording against those rungs before anyone quotes you theirs.

What P0455 sounds like: four clues you can hear

The loping idle after a fill-up. A purge valve stuck open floods the intake with vapour when the tank is fresh. Owners describe stalls, and one Focus owner an engine that "rumbles" for minutes before it settles.

The nozzle that keeps clicking off. The pump's shut-off hears the tank failing to breathe. That is the vent path of Route 2, not the cap.

The cap that never clicks. Toyota's Corolla bulletin is built around a "No Click" cap. A click you cannot feel or hear is worth a closer look.

The hiss when you open the cap. A sealed tank can hold slight pressure or vacuum, so a small puff is normal ⚪. A strong, long suction on a 2012-2018 Focus fits the "excessive vacuum" in recall 18V-735 ⚪.

Most owners hear trouble before any light comes on; our study of noises without a warning light shows how often.

What we counted in the federal complaint file

Our sample: every vehicle complaint added to NHTSA's public complaint files between 1 January 2015 and 8 September 2026, de-duplicated by report number: 777,040 unique owner reports, counted on 14 September 2026. We matched the exact code in the owner's description.

P0455 is rare in the file. 47 complaints name it; one more wrote P455 and we left it out. For comparison, 133 name P0456, 30 P0442, 28 P0441 and 12 P0446. No model has more than 3 P0455 complaints, so we rank nothing.

What the 47 describe. The fuel tank comes up in 15, the purge valve in 12, the cap in 11, the canister in 9, a smoke test in 8 and a failed inspection in 7. Five owners had already replaced the cap and still had the code; a 2007 Tahoe owner replaced the cap twice and the valves three times, a 2011 Suburban owner the purge valve four times. Where mileage was stated, in 27 reports, the median was 92,000 miles.

The Focus pattern sits under P0456. The Ford Focus accounts for 29 of the 133 P0456 complaints. Of those 29, 14 mention a stall or loss of power, 15 the purge valve, and 5 cite 18V-735 or Ford's 18S32, several saying their VIN was not listed.

Refuelling is the sound clue. Across the 234 complaints naming any of the five codes, 11 describe a stall, a hard start or rough running right after refuelling, and 8 of those are Fords. Two P0456 complaints cite recall 25V-467, but that is a fuel injector recall for the 1.5L Escape and Bronco Sport, not an EVAP one.

Clearing P0455 before an inspection: why it backfires

The light is an automatic fail. Under 40 CFR 85.2222, a vehicle whose check engine light is commanded on "shall fail the OBD inspection."

A cleared car is not ready. The same rule allows 2001 and newer vehicles no more than one unset readiness monitor, and clearing codes resets them all. The EVAP test needs its own conditions to run again.

A real leak comes straight back. Once the monitor runs, P0455 returns. The honest route is the repair, a week of driving and a readiness check with your own reader; the inspection cost guide covers re-test fees.

What actually happens at the shop, checkpoint by checkpoint

Checkpoint 1 — the VIN question. "What recalls, campaigns and extensions show on this VIN, and what is the in-service date?"

Checkpoint 2 — the full code list. "Which EVAP codes are stored with P0455, and did any purge or vent code appear?"

Checkpoint 3 — the leak test. "Did the system hold with the cap in place, and was it tested under pressure and vacuum?"

Checkpoint 4 — the proof. "Where did the smoke come out, and can I see a photo or the part?" Nissan and Ford both check returned parts.

Checkpoint 5 — the fee and the ceiling. "What does diagnosis cost, and will you call me before anything over this figure?" The overcharging guide covers how quotes inflate.

Three diagnostic traps that cost owners the most

Trap 1: the purge valve replaced on the code. The situation: P0455, car runs fine, 90,000 miles. What the shop says: "These purge valves always go. New valve." What is really happening: Ford found returned valves "fully functional" and requires two leak tests first; GM checks seven connections before any valve. Price versus bill: $50 to $150 for a smoke test, against $150 to $300 for a valve that may not be the leak. Your protective question: "Which test showed the valve leaking or stuck?"

Trap 2: the canister on a dusty truck. The situation: a 2021 Silverado used on gravel roads, P0455 and a slow fill. What the shop says: "Canister's plugged. Six hundred." What is really happening: GM's 2015 bulletin for earlier trucks says not to replace the canister unless it fails the leak test or has ingested excessive dirt, dust or water, and 23-NA-073 adds a vent filter so the dust stops. Price versus bill: a filter retrofit, against a canister that plugs again. Your protective question: "What stops the new canister filling with dust?"

Trap 3: the second cap and a blind smoke test. The situation: a new cap, the light back in a week, and smoke fed in through the filler neck. What the shop says: "Smoke test found nothing. Try another cap." What is really happening: Mazda warns that smoke through the filler adapter cannot detect a cap leak, and a test only under pressure can miss a leak that opens under vacuum. Price versus bill: one proper test, against caps bought monthly. Your protective question: "Where was the smoke connected, and was the cap tested separately?"

Three quotes, decoded

These are composite scenarios, not individual customers — the mileages and outcomes are typical of the patterns in the documents and complaints above, assembled so the arithmetic is visible. We do not publish invented testimonials.

Scenario 1 — the Nissan that needed nothing. A 2019 Rogue at 60,000 miles, P0455 three days after a fill-up. A quote of $450 for a canister and purge valve. The dealer runs NTB13-097J: the system holds for 10 minutes, the code is erased, no parts. Cost: a leak test. Lesson: a test that can pass is worth more than a part that might fix it.

Scenario 2 — the Focus on the list. A 2015 Focus 2.0L, stalls after refuelling, P0456 and P1450. An independent shop quotes $280 for a purge valve. The VIN is inside 18V-735; the dealer reprograms and replaces the valve free. Lesson: on a documented symptom, the VIN check comes before the quote.

Scenario 3 — the truck that kept plugging. A Sierra HD on a farm, P0455 twice in a year. The second canister quote is $600. The shop fits GM's 23-NA-073 filter, customer-paid, and adds it to the service schedule. Lesson: when the cause is the environment, the cheaper fix is the one that stops it recurring.

Your situation right now: four playbooks

"The light just came on after a fill-up." Clean and refit the cap, drive normally for a week, and watch.

"It stalls after refuelling." Keep the tank above half, run the VIN for recalls, and ask for a purge valve test.

"A shop quoted a canister or valve." Ask which test proved it and where the smoke was connected, in writing.

"It failed inspection." Fix, drive, confirm readiness with your own reader, then re-test. The check engine light guide covers the other codes.

After the fix: verify, then prevent

Verify the monitor, not the dark dashboard. After a week, a reader should show the EVAP monitor complete and no pending P0455.

Stop at the first click. Topping off after the pump shuts off is widely blamed for liquid fuel in canisters ⚪, and Ford's SSM 46525 says liquid fuel "should not be present" there.

Keep the vent side clean. On dusty trucks, check the vent filter as GM describes. Record 30 seconds of a healthy idle after a fill-up; the recording guide shows how.

Your action plan: 10 minutes, today, this week

Next 10 minutes — free:

1. Read and save the codes. Do not clear them.
2. Smell for liquid fuel; clean and refit the cap until it clicks.
3. Note how the last fill-up went.

Today:

4. Run the VIN through NHTSA and the manufacturer's owner site.
5. Record 30 seconds of idle after refuelling and run a free sound check.

This week:

6. If the light stays on, get a smoke test under pressure and vacuum.
7. Replace only the part a test condemned, then confirm the monitor completes.

Sources and documents

Primary documents, opened and read. Model years, build dates, populations and quoted phrases come from the documents themselves. ⚪ marks estimates and owner reports.

1. Nissan NTB13-097J and Infiniti ITB13-044J, 7 February 2022 — all 2012 and newer, cap first, 10-minute test. NTB13-097J · ITB13-044J
2. Nissan NTB09-020F and Infiniti ITB09-012F, 15 November 2013 — 2007-2011, loose cap. NTB09-020F · ITB09-012F
3. GM 21-NA-124, December 2022 — seven connections, pressure and vacuum. PDF
4. GM 23-NA-073, March 2025 — dust, filter retrofit, customer pay. PDF
5. GM 17-NA-383, December 2017 — spider nests in the canister inlet. PDF
6. GM 15-06-04-002, April 2015 — hard to fill, vent valve. PDF
7. GM PI0873, December 2012 — cap tether, cutaway vans. PDF
8. NHTSA recall 18V-735 (Ford 18S32) — 1,282,596 2012-2018 Focus, purge valve. Recall record
9. Ford SSM 50306, 2021 — test before replacing the purge valve. PDF
10. Ford SSM 46525, 2017 — liquid fuel in vapour lines. PDF
11. Ford SSM 51719, 2023 — cap debris and clicks. PDF
12. Ford SSM 49313, 2020 — canister damaged in transport. PDF
13. Ford TSB 16-0132, 2016 — 2017 Escape underhood line. PDF
14. Ford TSB 25-2308, 19 August 2025 — Maverick canister line. PDF
15. Ford TSB 25-2431, 12 September 2025, superseding 24-2199 — 2024 Edge vapour line in tank. 25-2431 · 24-2199
16. Kia SC135, Rev 1, 13 October 2016 — salt-belt canister campaign, 10-year extension. PDF
17. Kia PITSTOP PS469, January 2017 — manual EVAP test. PDF
18. Kia FUE033, January 2017; FUE040, April 2018; tech tip TT051, February 2014. FUE033 · FUE040 · TT051
19. Hyundai 17-01-003-1 (campaign 948), January 2017, and 21-FL-002H, June 2021. 17-01-003-1 · 21-FL-002H
20. Toyota T-SB-0086-16, 28 July 2016 — Corolla no-click cap, 36 months or 36,000 miles. PDF
21. Stellantis 14-005-22 REV. B, 12 August 2022; 25-002-15, 23 September 2015; 18-035-20, 8 April 2020. 14-005-22 · 25-002-15 · 18-035-20
22. Honda tech line article ATS 170206, October 2017; Acura 21-007, 22 September 2022; Acura 11-012, 12 February 2014. ATS 170206 · 21-007 · 11-012
23. Mazda 01-002/18, 30 January 2018 — locating the leak. PDF
24. Isuzu SB19-J-002, September 2019 — dusty-duty vent valve. PDF
25. Law and rules — 42 U.S.C. 7541 · 13 CCR 2037 · 13 CCR 1968.2 · 40 CFR 85.2222
26. Our complaint sample — 777,040 unique complaints, 1 January 2015 to 8 September 2026, exact code match; recall 25V-467 checked and excluded. Field definitions · 25V-467 record

What we looked for and did not find. NHTSA's index lists a 2015 GM bulletin on fuel odour during filling for full-size trucks with P0442 or P0455, but its PDF was not on NHTSA's server, so we make no claim from it. The index also attaches Acura 11-012 to dozens of Honda models; the document itself covers only the 2012 TL.

Related: gas smell, most expensive codes, P0420, P0171, Ford Fusion, diagnostic costs, our story.

Methodology. Documents were downloaded from NHTSA's server and read as text. Complaint counts come from NHTSA's complaint flat files, de-duplicated by report number; they are owner reports, not audited repairs. Prices were checked in September 2026 against published estimator summaries and our own cost guides; estimator pages refused automated access, so those figures come from search summaries. All are estimates marked ⚪. Coverage depends on your VIN.

Prices verified: September 2026 · Technical documents verified: September 2026 · Reviewed quarterly

Had a P0455 found and fixed, or paid for a part that did not fix it? Email [email protected] with the year, engine, mileage and the real cause — owner data is how these ranges get sharper.