P0442: EVAP system small leak detected
The ECU has detected a small leak in the fuel vapour system. It is often the fuel cap; if not, a hose or a valve.
| Code | P0442 |
|---|---|
| System | Engine and transmission |
| Group | P04xx, Emissions control |
| Type | Generic: it means the same on every make |
| Can you keep driving? | Yes, no rush |
What P0442 means
With the car parked or cruising gently, the ECU seals the vapour system and checks whether it holds pressure or vacuum. If it slowly loses it, there is a small leak, roughly the size of a one millimetre hole.
Most common causes
- Fuel cap not tightened or with a cracked seal
- Vapour hose with a small crack or a loose clip
- Canister vent valve not closing fully
- Leaking purge valve
- Filler neck or fuel pump seal
- Cracked canister
Symptoms
- Engine warning light on
- Sometimes a faint smell of petrol
- No change in how it drives
Can you drive with P0442?
Yes, no rush It does not affect the engine or safety. You can drive normally and track down the leak when convenient.
Open the bonnetthe in-depth explanation
How to check it
Check the fuel cap: it should click shut and the rubber seal should not be cracked. If the code returns, a garage can find the leak with a smoke test.
How to read and clear P0442 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0442 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P043E The reference opening for detecting fuel vapour leaks has low flow
- P043F The fuel vapour leak detector reference opening has excessive flow
- P0440 Evaporative emission (EVAP) system malfunction
- P0441 EVAP system incorrect purge flow
- P0443 EVAP purge control valve circuit malfunction
- P0444 EVAP purge control valve circuit open
- P0445 EVAP purge control valve circuit shorted
- P0446 EVAP vent control circuit malfunction
- P0400 Exhaust gas recirculation (EGR) flow malfunction
- P0401 Exhaust gas recirculation (EGR) flow insufficient
- P0402 Exhaust gas recirculation (EGR) flow excessive
- P0403 EGR control circuit malfunction
What does code P0442 mean?
With the car parked or cruising gently, the ECU seals the vapour system and checks whether it holds pressure or vacuum. If it slowly loses it, there is a small leak, roughly the size of a one millimetre hole.
Can you drive with P0442?
It does not affect the engine or safety. You can drive normally and track down the leak when convenient.
How do you clear P0442?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0442 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
