P0442 on Mazda
Evaporative Emission Control System Leak Detected (Small Leak)
P0442 on Mazda vehicles indicates evaporative emission control system leak detected (small leak). Au7o has documented this code across 1 Mazda model — most commonly on Mazda5. 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 Mazda range from $800 to $1,800, 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 Mazda by Model
Mazda Mazda5(1 issue)
- A/C Evaporator Core Leak2006-2015
The A/C evaporator core in the Mazda5 develops pinhole leaks from internal corrosion, causing refrigerant loss. The evaporator is located behind the dashboard, making replacement extremely labor-intensive. Corrosion is accelerated by moisture trapped in the cabin air filter area and infrequent cabin filter replacement.
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View P0442 across all makes →Frequently Asked Questions
What does P0442 mean on Mazda?▼
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 Mazda specifically, this code is documented across 1 model.
What causes P0442 on Mazda vehicles?▼
Common causes on Mazda: 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 Mazda?▼
Repair costs on Mazda range from $800 to $1,800, depending on the specific model and root cause.
Which Mazda models have P0442 documented?▼
Au7o has documented P0442 on 1 Mazda model: Mazda5.