Evaporative emissions (EVAP)
P0442
Evaporative Emission System Leak Detected (Small Leak)
What does P0442 mean?
P0442 means the evaporative emissions system, which captures fuel vapour from the tank and stops it reaching the atmosphere, is leaking somewhere. The computer pressurises or vacuums the system and watches whether it holds. A small leak is roughly the size of a pinhole — often just a loose fuel cap.
Can I keep driving with P0442?
Low urgency
Safe to drive and not a mechanical risk. It will fail an emissions test, and the cheapest possible fix — tightening or replacing the fuel cap — is worth trying first.
Symptoms of P0442
Check engine light with no change in how the car drives
Occasionally a faint fuel smell near the rear of the vehicle
Failed emissions test
Common causes of P0442
A loose, cracked or worn fuel filler cap — always check this first
A cracked or perished EVAP hose
A leaking purge or vent valve
A small crack in the charcoal canister
These are ordered roughly by how often they turn out to be the cause — but the code names a system, not a part. Confirming which one is yours takes data from the running engine.
What does it cost to fix P0442?
$20 – $600
Typical US independent-shop range, parts and labour included. It is wide on purpose: the cheap end is usually a sensor, a hose or a cap, and the expensive end is the major component the code was reporting on. Which one you need is a diagnosis, not a guess — and dealer rates run higher than these figures.
What does P0442 mean for your car?
This page explains what P0442 means in general. It cannot tell you which of those causes is yours, because that answer is in your car's own data. Kaiju Mechanic reads the codes your car is actually storing, plus live sensor data through any standard ELM327 adapter, and interprets it against your exact year, make, model and mileage. You can also just ask it about P0442 in chat — no adapter needed for that.
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