P0442: EVAP System Leak Detected (small leak)
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - purely an emissions code with zero effect on drivability.
Symptoms
- Check engine light only
- Occasional fuel smell near the filler in severe cases
Likely causes, most common first
- Loose or aging gas cap (still the first check)
- Cracked EVAP hose or filler neck
- Leaking purge or vent valve seal
Read P0442 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0442 reports a small leak - roughly the size of a 1 mm hole - in the evaporative emissions system that keeps gasoline vapors out of the atmosphere. Nothing about engine operation changes; the tank vapor system just is not sealing.
Tighten or replace the gas cap first, clear the code and drive a few days. If it returns, a shop smoke test finds the leak visually - chasing EVAP leaks without smoke is guesswork. Fix it before your next emissions inspection; otherwise it is a harmless but persistent light.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0442
“On Sept 6th the check engine light came on. A diagnostic test showed it was code P0442 related to the canister purge valve /solenoid. It also showed that it was a permanent thing that had been on there a while but when I look up my Vin number there is no recalls for it, but there is for other 2019 Buick enclaves.”2019 Buick Enclave · Sep 2024
“Check engine light came on. P0442 code. Brought for service. Needed to replace fuel components but frame too rusted to mount parts. Told to see body shop for repair if possible. No rust on bed or body . Body shop could not repair frame. Body shop said frame is no longer safe to drive. Unable to pass state inspection. 97000 mi , no commercial use. Well maintained.”2014 Chevrolet Silverado 1500 · Sep 2024
“warning light came on checked code p0442 came up stating a small vapor leak in fuel system. replaced fuel cap , smoke test and found that the evap vent solenoid was leaking. Remove and replace fuel tank vent valve program module. Still smelled fuel. Took vette to a dealership had them do a multipoint inspection they pinpointed and diagnose the problem as the left side fuel tank module and all necessary gaskets and seals needed to be replace at a out of this world price. I believe this to be a safety risk.”2009 Chevrolet Corvette · Dec 2023
Show 7 more owner reports
“fuel tank leaking gasoline from tanks seams and hose nipple, second owned vehicle with same problem. now the vehicle has strong gas smell and is leaking gasoline when driven in a incline. It threw a p0442 "evap leak small" thats why i checked the fault. All these steel tanks seem to rust where the seam of the tank is, and also the filler neck tube connects to the tank, one of the evap hoses was just hanging next to the fuel tank, the nipple that holds it to the tank rusted and came off.”2009 Subaru Forester · Jul 2023
“Check engine light comes on and has a p0442. I can smell fuel after light comes on mostly and lower speeds (under 10 mph) and always at a stop. When I fill up it is a definite under both circumstances. I was pointed to a new gas cap. I've replaced 2 and the code continues to return and the smell of fuel is outstanding and seems unsafe for the potency.”2011 Chevrolet Corvette · Sep 2020 · 52,000 mi
“Fuel filler neck is defective causing code p0442. Car VIN was never part of recall. I should get reimbursed for this repair.”2004 Mitsubishi Endeavor · Aug 2019
“Purchased 2019 equinox had 957 miles on it when "check engine" light appeared. Took it into dealership and they said code was p0442 evap small leak. They found purge tube not seated fully. Prior to driving it into dealership we smelt gas fumes in the interior cabin. 23 days later "check engine" light appeared at 1426 miles. Heard loud pop coming from rear of car. Again gas fumes can be smelt in the interior cabin. Dealership said code p0442 again but it was from the evap canister "o" ring failure. This emission system seems faulty as it is a sealed unit but smelling gas fumes in the interior is not safe at all.”2019 Chevrolet Equinox · Jul 2019 · 1,426 mi
“P0442(evap small leak) using evap tool j-41413-200,pressure tested the evap system while performing system seal.found that the evap purge solenoid is leaking.plugged the evap purge solenoid port and found evap pressure loss not present. Reviewed tech 685 and 201 history.parts warranty cause:failed purge solenoid failure installed new evap purge solenoid.retested and verified system seal. Gm parts warranty lo: 4025690 1.2 0329/6579 original ro# 495351 58101 miles 03/14/2019 I had this car in for the same repair march 14, 2019 and again june 26, 2019. What is wrong with this car that this part goes out so often?”2015 Chevrolet Impala · Jun 2019
“Strong gasoline odor after filling gas tank full. Check engine light comes on. Diagnostic code p0442 on car computer. No gas odor when filling tank only one-half full.”2013 Chevrolet Corvette · Jul 2017 · 13,361 mi
“2015 chevrolet sonic hatchback ltz- fuel filler tube leaking at tank connection, causing gas to spill out on ground. Could be a potential a fire/explosion hazzard. Discovered when check engine light was activated. Ran an odbii code check indicating a p0442 error "emission system leak-small". Observed gas flowing to the ground as the car was being filled with gas. Had the car less than 1-week after purchasing "used" with 19k miles.”2015 Chevrolet Sonic · May 2016 · 19,890 mi
Cars that report P0442 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0442?
Yes - purely an emissions code with zero effect on drivability.
How much does it cost to fix P0442?
Typical US repair costs range from $10 for the simplest fix (gas cap) to $400 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.