P0442
Fix within 1-2 weeksYour vehicle's computer detected a small leak in the evaporative emissions (EVAP) system. This system prevents fuel vapors from escaping into the atmosphere.
Code P0442 means a small leak in your EVAP system. Common causes: Gas cap (40%), purge valve (25%), vent valve (20%). Drivability: Yes, safe to drive. Repair cost: $15-$300 DIY, $100-$600 professional.
Can I Drive With P0442?
Yes, safe to drive
No restrictions
Stop driving immediately if: None, P0442 does not typically cause immediate drivability issues.
Symptoms of P0442
- 1Check Engine Light is on
- 2Faint smell of fuel around the vehicle (sometimes)
Common Causes of P0442
Parts most likely causing this code, ranked by probability
A loose, damaged, or incorrect gas cap is the most common cause of a small EVAP leak.
40% of P0442 cases are fixed by replacing the gas cap
A faulty purge valve can stick open or closed, allowing fuel vapors to escape or preventing proper system operation.
25% of P0442 cases are fixed by replacing the EVAP purge valve
A vent valve that fails to seal properly will create a small leak in the EVAP system.
20% of P0442 cases are fixed by replacing the EVAP vent valve
Cracked, disconnected, or damaged vacuum hoses and lines in the EVAP system can cause small leaks.
10% of P0442 cases are fixed by repairing or replacing EVAP hoses
A cracked charcoal canister or a leaking gasket around the fuel tank sending unit can allow small amounts of fuel vapor to escape.
5% of P0442 cases are fixed by replacing the charcoal canister or fuel tank gasket
Check These First (Before Buying Parts)
- Ensure your gas cap is tight. Remove it, then re-tighten it until it clicks several times.
- Visually inspect your gas cap for any cracks, damage, or a worn-out rubber seal.
- Look under the hood and around the fuel tank for any obvious disconnected, cracked, or damaged EVAP hoses.
How to Diagnose P0442
- 1Tighten or replace your gas cap. Clear the code and drive to see if it returns.
- 2Visually inspect all accessible EVAP hoses and lines for cracks, disconnections, or damage.
- 3Locate and inspect the EVAP purge valve and vent valve for any visible damage or signs of leakage.
- 4Use a smoke machine (professional tool) to pinpoint the exact location of the small leak in the EVAP system.
- 5Test the purge and vent valves using a scan tool to command them open and closed, checking for proper operation.
P0442 on Popular Vehicles
Toyota Camry
2007-2024P0442 on Toyota Camry models is often traced to a faulty EVAP purge valve or a cracked EVAP hose near the charcoal canister. Always check the gas cap first.
65% fixed by gas cap or purge valve replacement
Honda Accord
2003-2024Honda Accords frequently experience P0442 due to issues with the EVAP vent valve (located near the charcoal canister) or the EVAP purge valve. A non-sealing gas cap is also a very common cause.
70% fixed by gas cap or vent/purge valve replacement
Ford F-150
2004-2024For Ford F-150 trucks, P0442 is commonly caused by a failing EVAP purge valve or a cracked EVAP hose, especially those connected to the charcoal canister. The gas cap is a simple first check.
60% fixed by gas cap or purge valve replacement
Chevrolet Silverado
2007-2024Chevrolet Silverado trucks often trigger P0442 due to a faulty EVAP vent valve or purge valve. Inspecting the rubber hoses for cracks or loose connections is also important after checking the gas cap.
65% fixed by gas cap or vent/purge valve replacement
Frequently Asked Questions
What does P0442 mean?
P0442 indicates that your vehicle's engine computer has detected a small leak in the Evaporative Emission Control System, which is designed to capture and store fuel vapors.
Can I drive with P0442?
Yes, you can drive safely with a P0442 code. This code does not typically cause immediate drivability issues or engine damage. However, you should fix it within 1-2 weeks to prevent emissions system problems and pass inspections.
Will P0442 clear itself?
No, P0442 will not clear itself. After fixing the leak, you will need to drive several complete drive cycles for the computer to re-run its EVAP system tests. Clearing the code with an OBD-II scanner is the fastest way to turn off the Check Engine Light after a repair.
How do I fix P0442 myself?
Start by tightening or replacing your gas cap. If that does not work, visually inspect all EVAP hoses for cracks or disconnections. If the issue persists, you may need to replace the EVAP purge valve or vent valve, which are often accessible with basic hand tools.
How much does it cost to fix P0442?
DIY repair costs range from $15 for a new gas cap to $300 for a new EVAP purge or vent valve. Professional repair costs typically range from $100 to $600, including diagnosis and parts replacement.
P0442 keeps coming back - why?
If P0442 keeps returning, it means the original leak was not fully resolved, or there is another leak present. Common reasons include a faulty replacement part, a leak in a different part of the EVAP system (like a hose you missed), or a more complex issue requiring a smoke test to locate.
Will P0442 fail emissions/smog test?
Yes, a P0442 code will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on for any EVAP system fault means the system is not ready or is actively failing.
What's the difference between P0442 and P0455?
P0442 indicates a 'small leak' in the EVAP system, meaning a minor opening. P0455 indicates a 'large leak' in the EVAP system, which is a more significant opening, often caused by a completely missing gas cap or a major hose disconnection.
P0442 on Honda Accord
On many Honda Accord models, P0442 is frequently caused by a faulty EVAP purge valve or EVAP vent valve. The gas cap is also a common culprit. Start with the gas cap, then inspect and test the purge and vent valves.
Questions to Ask Your Mechanic
Did you perform a smoke test on the EVAP system to pinpoint the leak?
Good answer: Yes, we connected a smoke machine to the EVAP system and observed smoke escaping from [specific part, e.g., a cracked hose near the canister].
What were the results of testing the EVAP purge and vent valves?
Good answer: We tested both valves using a scan tool. The purge valve was not sealing completely when closed, or the vent valve was stuck open, causing the leak.
Repair Cost Estimate
DIY Repair
Parts only
$15-$300
Shop Repair
Parts + labor
$100-$600
Save $85-$300 by doing it yourself
Difficulty
beginner
Time
0.5-2 hours
Beginner-friendly. Many P0442 causes, like a gas cap or accessible EVAP valves, are simple to diagnose and replace with basic tools.
Cost of Waiting
Ignoring a P0442 code will cause your vehicle to fail emissions inspections. While it does not cause immediate damage, it means your vehicle is releasing harmful fuel vapors into the atmosphere. A $20 gas cap fix now prevents a failed inspection and potential re-test fees later.
While You're In There...
If you are replacing the vent valve or canister, checking or replacing the canister filter can prevent future issues, as a clogged filter can affect EVAP system performance.
Tools You'll Need
- Basic hand tools (screwdrivers, pliers, wrenches)
- OBD-II scan tool (to clear code)
- Flashlight
P0442 is a very common emissions code. Most repairs are straightforward, often just a gas cap, and your vehicle will pass emissions tests afterward.
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Your Next Steps
Step 1: Tighten or replace your gas cap. Clear the code with an OBD-II scanner and drive for a few days to see if the light returns.
Step 2: If the light returns, visually inspect all accessible EVAP hoses and lines for cracks, loose connections, or damage. Pay close attention to hoses near the fuel tank and engine.
Step 3: If no obvious hose issues are found, consider replacing the EVAP purge valve or vent valve, as these are common failure points for small leaks. You may need to test them first if you have a diagnostic scan tool that can activate them.