What does P0442 mean?
The computer found a small leak in the evaporative emission system, roughly the size of a 0.040-inch hole. Small leaks are often a worn fuel cap seal or a cracked hose.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Possible fuel smell
- Hard starting after refueling (with purge problems)
- No change in how the car drives in most cases
Common causes
- Worn fuel cap seal
- Small crack in an EVAP hose
- Leaking purge or vent valve
- Leaking leak-detection pump or ESIM switch on some vehicles
How to diagnose P0442
- Check the fuel cap and its seal first.
- Run a smoke test, the most reliable way to find EVAP leaks.
- Command the purge and vent valves with a scan tool and check that they open and seal.
- Inspect the filler neck and hoses under the vehicle.
How to fix it
- Replace the fuel cap
- Replace cracked hoses
- Replace the purge or vent valve
- Replace the charcoal canister or filler neck
Estimated repair cost
Likely repairs for P0442 run from about $15 to $700, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Fuel cap replacement | $15 - $45 |
| EVAP smoke test | $100 - $200 |
| EVAP purge valve | $100 - $300 |
| EVAP vent valve/solenoid | $100 - $350 |
| Charcoal canister replacement | $250 - $700 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0442?
Low severity
Safe to drive. It will fail an emissions test until fixed.
Make-specific notes
Chrysler / Dodge / Jeep
Many use a leak detection pump (LDP) or an ESIM switch near the canister that can fail.
Ford
A sticking canister vent solenoid and cracked hoses are common causes.
Always check open recalls and technical service bulletins for your VIN.
P0442 FAQ
Can I drive with P0442?
Yes. It does not affect how the engine runs, but it will fail an emissions test.
How do shops find small EVAP leaks?
With a smoke machine. It pushes visible smoke into the system so the leak shows up.
What does P0442 mean?
P0442 stands for "Evaporative Emission System Leak Detected (Small Leak)". The computer found a small leak in the evaporative emission system, roughly the size of a 0.040-inch hole.
How much does it cost to fix P0442?
It depends on the cause. The likely repairs for P0442 range from about $15 to $700 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0442?
The most common causes are: worn fuel cap seal; small crack in an EVAP hose; leaking purge or vent valve.