P0457: EVAP system leak: fuel cap loose or missing
The ECU has found a leak in the vapour system right after refuelling, which points to a fuel cap that is loose or has been left off.
| Code | P0457 |
|---|---|
| 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 P0457 means
After you fill up, the ECU checks that the petrol vapour circuit is sealed. If it finds an obvious leak at that point, the most likely reason is a cap that was not tightened properly or was left behind at the pump.
Most common causes
- Fuel cap not tightened until it clicks
- Cap left behind or lost
- Damaged or dirty cap seal
- Damaged filler neck that stops the cap sealing
- Non-original cap that does not fit
Symptoms
- Engine warning light comes on shortly after refuelling
- On some cars, a fuel cap message on the dashboard
- Possible smell of petrol
Can you drive with P0457?
Yes, no rush You can drive as normal. Tighten or replace the cap as soon as you can so vapour stops escaping.
Open the bonnetthe in-depth explanation
How to check it
Tighten the cap until it clicks, clear the code and drive for a few days. If it comes back with the cap properly fitted, check the seal or replace the cap.
How to read and clear P0457 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 P0457 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
- P0453 EVAP pressure sensor circuit high
- P0454 EVAP system pressure sensor intermittent signal
- P0455 EVAP system large leak detected
- P0456 EVAP system very small leak detected
- P0458 EVAP purge control valve circuit low
- P0459 EVAP purge control valve circuit high
- P045A The exhaust gas recirculation B control has an electrical fault
- P045B The exhaust gas recirculation B control gives readings outside the normal range
- 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 P0457 mean?
After you fill up, the ECU checks that the petrol vapour circuit is sealed. If it finds an obvious leak at that point, the most likely reason is a cap that was not tightened properly or was left behind at the pump.
Can you drive with P0457?
You can drive as normal. Tighten or replace the cap as soon as you can so vapour stops escaping.
How do you clear P0457?
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, P0457 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.
