P0442 on Honda: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Small Leak)
3 Honda models · 3 documented issues · $20-$400 repair
P0442 on Honda by model: symptoms, diagnosis and fix
P0442 sets when the Civic's PCM runs its EVAP self-test and detects a small leak (roughly 0.020-0.040 in). On the Civic the overwhelmingly most common source is the fuel-filler cap: the rubber O-ring on the cap hardens and shrinks with age/heat and stops sealing, which is why a P0442 frequently appears first and later escalates to a P0455 gross leak as the same gasket worsens. After the cap, the usual Civic culprits are cracked/perished EVAP vapor hoses (heat-aged rubber near the engine bay and along the tank), a purge solenoid or canister vent valve not sealing, or a leaking charcoal canister. It is common across all EVAP-equipped generations but very typical on high-mileage 8th-gen (2006-2011) and 9th-gen (2012-2015) cars.
Common Symptoms
- Check Engine Light on (usually no drivability change)
- Faint fuel smell in some cases
- Code sometimes clears then returns after refueling
- May fail an emissions readiness/smog check
How to Fix
Start with the cheapest, highest-probability fix: remove and inspect the gas cap, confirm it clicks/ratchets, and if the O-ring is cracked or flattened replace it with a genuine Honda OEM cap (aftermarket caps often fail to seal). Clear the code and drive several drive cycles. If it returns, smoke-test the EVAP system to find cracked vapor lines or a leaking purge/vent valve, then replace the failed component. Verify the canister and its fittings are intact. Genuine Honda cap first, smoke test second is the accepted diagnostic order.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Honda 17670-T3W-A01 fuel-filler capOEMHonda 17670-T3W-A01
First-line capped-system replacement only when the cap seal or ratchet fails inspection Fitment/availability: Honda catalog fitment for capped 2006-2015 Civic applications; supersedes 17670-SNA-A02 and 17670-TR0-A01/A11. Enter VIN.
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Sources for this issue (3)
P0442 sets when the CR-V's ECM runs its EVAP self-test and detects a small vapor leak (roughly 0.020 in.) in the sealed fuel-vapor system. On the CR-V the culprit hierarchy is well established: first a loose, worn, or non-OEM fuel filler cap that no longer seals its O-ring; then the canister purge valve (vent-purge solenoid) on the engine that leaks by; and finally the canister vent valve at the rear charcoal canister. Because the leak is tiny, there are no drivability effects — it is purely an emissions/monitor fault, but it will fail an OBD emissions/smog test and keep the check-engine light on.
Common Symptoms
- Check-engine light on with no drivability change
- No loss of power or fuel economy
- Fails state emissions/smog test
- Occasional faint fuel odor near the cap
How to Fix
Start by removing and re-seating the fuel cap until it clicks, then clear the code and drive several trips. If it returns, replace the cap with a genuine Honda cap (aftermarket caps frequently do not seal on Hondas). If the cap is good, smoke-test the system to find the leak, then replace the canister purge valve or vent valve as indicated. Confirm the EVAP monitor completes and stays ready.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Honda 17670-S5A-A32 fuel-filler capOEMHonda 17670-S5A-A32
Confirm VIN; not for 2005+ or any capless 2017+ model.
- Genuine Honda 17670-SHJ-A02 fuel-filler capOEMHonda 17670-SHJ-A02
Replacement cap only after the original cap/seal fails inspection or testing Fitment/availability: 2005-2006 CR-V capped-filler branch as cataloged. Current replacement for 17670-SHJ-A31/A01; not for 2002-2004 or 2007+ CR-V.
- Genuine Honda 17670-T3W-A01 fuel-filler capOEMHonda 17670-T3W-A01
Confirm VIN; this part does not fit the capless 2017-2022 CR-V despite the source's broad claim.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
On the Honda Accord, P0442 (small EVAP leak) is one of the most common check-engine triggers and almost always traces to one of three components in order of likelihood: the fuel cap, the engine-bay canister purge valve, or the under-car canister vent solenoid. The gas cap's rubber O-ring hardens, cracks, and stops sealing with age (aftermarket caps are a frequent repeat offender on this model). When the cap is good, the electric canister purge valve (which sticks or leaks internally) and the vent solenoid are the next suspects. A common Honda giveaway is a P1457 or P0451/P0456 stored alongside P0442, which points to the canister vent-side hardware rather than the cap. Because the leak is small, it is often intermittent and may set after refueling.
Common Symptoms
- Check engine light on
- Occasional faint fuel odor
- No drivability change
- Code often returns after refueling
- Sometimes paired with 'check fuel cap' message
How to Fix
Start with the cheapest fix: inspect and replace the OEM fuel cap (Honda P/N 17670-SDA-A02 family) with a genuine Honda cap, then clear the code and drive several drive cycles. If it returns, perform an EVAP smoke test to pinpoint the leak; the usual repair is replacing the canister purge valve (engine bay) or the vent solenoid (under the car near the charcoal canister). Avoid aftermarket gas caps, which commonly reseal poorly.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Honda 17670-SDA-A01 fuel-filler capOEMHonda 17670-SDA-A01
The catalog shows broad 2003-2004 coverage but narrower 2005 coverage; use VIN confirmation for 20
- Honda 17670-SHJ-A02 fuel-tank capOEMHonda 17670-SHJ-A02
Replace a confirmed failed cap on the later seventh-generation branch Fitment/availability: Selected 2005-2007 Accord configurations; supersedes 17670-SHJ-A01 and 17670-SHJ-A31.
- Honda 17670-T3W-A01 complete fuel-filler capOEMHonda 17670-T3W-A01
Replace a confirmed failed cap-seal branch on the eighth- or ninth-generation car Fitment/availability: 2008-2017 Accord L4 or V6 in the seller's listed US configurations.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
P0442 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0442 mean on a Honda?
P0442 stands for "Evaporative Emission Control System Leak Detected (Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it. On Honda it is documented across 3 models: Civic, CR-V, Accord.
What are the most common causes of P0442?
The most common causes of P0442 are: Loose, damaged, or missing fuel filler cap, Worn or cracked gas cap seal, Cracked or disconnected EVAP hose or line, Faulty purge valve or vent valve, Damaged O-ring or seal at the fuel tank or filler neck, Small crack in the charcoal canister, Leaking fuel tank sending unit gasket. The specific cause varies by vehicle.
How much does it cost to fix P0442 on a Honda?
Published repair estimates on Honda range from $20 to $400 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0442 on a different make?
View P0442 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.