P0442 on Chevrolet: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Small Leak)
5 Chevrolet models · 5 documented issues · 1 critical · $20-$500 repair
P0442 on Chevrolet by model: symptoms, diagnosis and fix
The HHR has a documented issue with fuel line corrosion, particularly in rust belt states. The fuel line corrodes just forward of the driver-side rear wheel, developing leaks that create a fire hazard. Road salt and debris accelerate the corrosion. The issue is most commonly seen on vehicles in the northeastern and midwestern United States where road salt is used heavily in winter.
Common Symptoms
- Gasoline smell near the vehicle
- Visible fuel drip under vehicle near rear driver-side wheel
- Fuel economy decreasing noticeably
- Rust or corrosion visible on fuel lines during inspection
- Check engine light with evaporative system codes
How to Fix
Inspect fuel lines annually, especially near the driver-side rear wheel. If corrosion is found, replace the affected fuel line section with stainless steel or nylon-coated replacement lines. Do not use tape or sealant on fuel lines - full section replacement is required. Cost is $200-$500 at an independent shop.
Sources for this issue (1)
P0442 sets when the ECM detects a small evaporative-system leak — roughly a 0.020–0.040 inch hole's worth of pressure loss. On the Equinox this code follows a clear hierarchy of culprits. The single most common cause across all years is a degraded gas-cap O-ring that no longer seals (or a cap not clicked tight after refueling). On the second-generation 2.4L (LEA/LAF) and V6 models, the next most frequent offenders are the EVAP purge solenoid and the canister vent solenoid, which stick or leak internally. A cause that is distinctly an Equinox/Terrain pattern — especially in salt-belt states — is the metal EVAP line running under the driver's-side frame rail rusting through, which no amount of solenoid or gas-cap replacement will fix.
Common Symptoms
- Check engine light on
- Occasional faint fuel odor near the tank
- Hard start immediately after refueling (when purge/vent related)
- No performance change; passes as a 'small leak'
- May fail emissions inspection
How to Fix
Start with the cheapest, most likely fix: inspect the gas-cap O-ring for cracking/dry-rot and re-tighten until it clicks several times; replace with an OEM ACDelco cap if the seal is degraded. If the cap is good, perform a smoke test — this is the key step that separates a leaking purge/vent solenoid from a rusted-through metal EVAP line under the vehicle. Replace the purge or vent solenoid only if the smoke test localizes the leak there; if the underbody EVAP line is rusted, replace the line rather than throwing solenoids at it. Clear the code and complete a drive cycle to confirm.
Sources for this issue (1)
P0442 flags a small EVAP leak (roughly a 0.020-0.040 inch hole). On 2012-2016 Malibus with a conventional threaded gas cap, the most common cause is a cracked or flattened cap O-ring. On the 2016+ ninth-gen cars with the capless fuel filler, the culprit is usually the filler-neck seal or debris holding the spring-loaded flap slightly open. On all years, a leaking or weak EVAP purge valve — a well-known failure across GM platforms of this era — is the next most likely source. Cracked charcoal-canister hoses round out the list.
Common Symptoms
- Check engine light
- Faint fuel vapor smell
- No drivability change
- Failed emissions/readiness test
How to Fix
Start with the cheapest checks: inspect/replace the gas cap and O-ring (or clear debris and inspect the capless filler seal on 2016+). If that does not resolve it, replace the EVAP purge valve. When the simple items check out, run a professional smoke test to pinpoint the leak (canister, hoses, or vent valve) and repair the leaking component.
Sources for this issue (1)
A very common GMT800 Silverado problem is contamination of the EVAP canister vent valve/solenoid by dust, road debris, or water intrusion. When the vent cannot flow properly, the truck sets EVAP leak or vent performance codes and may repeatedly shut off the gas pump during refueling. GM issued service bulletins and updated vent relocation kits for trucks used in dusty environments.
Common Symptoms
- check engine light
- fuel nozzle clicks off repeatedly while filling
- EVAP small or large leak codes
- failed emissions inspection
- intermittent fuel smell near rear of truck
How to Fix
Diagnosis includes smoke testing the EVAP system, commanding the vent valve with a scan tool, and inspecting the vent hose/filter for blockage. Repair usually involves replacing the vent solenoid and installing the updated relocated vent hose/filter kit to move the inlet away from road splash and dust. Clearing codes without updating the vent routing often leads to repeat failures.
Sources for this issue (1)
On the 3.6L V6 (RPO LFY) Traverse, the evaporative emissions purge valve can fail to fully close, allowing fuel vapor to flood the intake. This causes a P0496 (EVAP high purge flow) code with rough running, hesitation, or stalling at idle, and hard starting after refueling. GM acknowledged the condition and issued Special Coverage N232395300 (15 years / 150,000 miles) to replace the purge valve at no charge on affected 2019 Traverse units.
Common Symptoms
- Check engine light with P0496
- Rough idle or stalling at idle
- Hard starting after refueling
- Engine hesitation
How to Fix
Replace the failed evaporative emission purge/solenoid valve (free under GM Special Coverage N232395300 on eligible 2019 3.6L units); clear P0496 and verify EVAP system seal. Check for related EVAP codes (P0442, P0455) that can accompany the failure.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- EVAP canister purge solenoid valve (GM Genuine / ACDelco)OEM12737252Cross-refGM 12690512 (prior number, superseded by 12737252), Standard Motor Products CP612, Standard Motor Products CP612T$15–$36
This is the part GM's Special Coverage N232395300 bulletin (NHTSA MC-10238343) lists for the 3.6L LFY Traverse/Enclave: Purge Solenoid Valve 12690512. GM has since superseded 12690512 with 12737252 (GM Parts Giant product page states 'Re…
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 Chevrolet?
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 Chevrolet it is documented across 5 models: HHR, Equinox, Malibu, Silverado 1500, Traverse.
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 Chevrolet?
Published repair estimates on Chevrolet range from $20 to $500 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.