P0442 on Subaru
Evaporative Emission Control System Leak Detected (Small Leak)
P0442 on Subaru vehicles indicates evaporative emission control system leak detected (small leak). Au7o has documented this code across 2 Subaru models — most commonly on Outback, WRX. 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. Typical repair costs on Subaru range from $20 to $900, depending on the specific model and root cause.
Common Causes of P0442
- •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
P0442 on Subaru by Model
Subaru Outback(1 issue)
- P0442 — Small EVAP Leak from Gas Cap O-Ring or Leaking Purge/Vent Valve2005-2022
P0442 means the ECM detected a small leak in the sealed evaporative-emissions system during its self-test. On the Outback the three usual culprits, in order, are: (1) the fuel filler cap — its rubber O-ring hardens and cracks with age, or the cap isn't clicked tight, or a non-OEM cap seals poorly; (2) the EVAP purge valve (solenoid), which should hold vacuum but starts to weep past its internal seal; and (3) the vent valve on/near the charcoal canister, which can't seal during the leak test if dirt or corrosion is present. Because the leak is tiny, drivers usually notice nothing but the check-engine light, and the code is often intermittent (comes and goes with temperature and fuel level).
Subaru WRX(1 issue)
- Fuel Filler Neck Corrosion Causing EVAP Leaks, Fuel Smell, and Check-Engine Light2002-2007
Rust-belt GD-chassis WRX models are known for corrosion of the steel fuel filler neck and vent tubes behind the left rear wheel area. As the neck rusts through, owners notice a raw fuel smell, difficulty filling the tank, or EVAP leak codes from the compromised venting system. Subaru issued recalls and service campaigns on related Impreza models in salt-belt states because the corrosion could lead to fuel leakage.
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What does P0442 mean on Subaru?▼
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 Subaru specifically, this code is documented across 2 models.
What causes P0442 on Subaru vehicles?▼
Common causes on Subaru: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0442 on a Subaru?▼
Repair costs on Subaru range from $20 to $900, depending on the specific model and root cause.
Which Subaru models have P0442 documented?▼
Au7o has documented P0442 on 2 Subaru models: Outback, WRX.