P0455: Evaporative Emission System Leak Detected (Large Leak)
The EVAP system found a large leak. The most common cause is a gas cap left loose or off.
Green, yellow, red: three ways P0455 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Gas cap was loose. Tighten it and drive a few days; the light usually clears.
Schedule a repair
The cap is fine and the code returns. Schedule a smoke test.
Stop and get help
Strong fuel smell or dripping fuel. Don't drive it.
Symptoms you might notice
- Usually none
- Fuel smell
Common causes, cheapest first
- Gas cap loose, missing or wrong
- Disconnected or cracked EVAP hose
- Purge or vent valve stuck open
What you can check before calling
- Check the gas cap first
- Smell for fuel near the tank
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Want the full story? Read our guide: Check engine light after getting gas? Gas caps and EVAP codes.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More evap (fuel vapor) codes
- P0440
Evaporative Emission System Malfunction - P0441
Evaporative Emission System Incorrect Purge Flow - P0446
Evaporative Emission System Vent Control Circuit Malfunction - P0449
Evaporative Emission System Vent Valve/Solenoid Circuit Malfunction - P0457
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off) - P0496
Evaporative Emission System High Purge Flow
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0455 mean?
P0455 means "Evaporative Emission System Leak Detected (Large Leak)". The EVAP system found a large leak. The most common cause is a gas cap left loose or off.
Can I drive with code P0455?
It depends on what the vehicle is doing. Green: Gas cap was loose. Tighten it and drive a few days; the light usually clears. Yellow: The cap is fine and the code returns. Schedule a smoke test. Red: Strong fuel smell or dripping fuel. Don't drive it.
What causes P0455?
The most common causes are: gas cap loose, missing or wrong; disconnected or cracked EVAP hose; purge or vent valve stuck open.
Is P0455 a serious code?
It can be. Strong fuel smell or dripping fuel. Don't drive it.
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