What P0455 means
Diagnostic Trouble Code (DTC) P0455 stands for Evaporative Emission System Leak Detected (Gross Leak). This is a generic OBD2 diagnostic trouble code indicating that the engine computer (ECU) has registered an operational anomaly in the powertrain (p) systems.
When this error registers, the ECU records a freeze frame of sensor data and lights up the Check Engine Light on your dashboard to notify the operator of a system fault.
Symptoms of OBD2 Code P0455
When code P0455 is active, your car might exhibit the following common symptoms:
- Check Engine Light (MIL) illuminated
- Slight fuel odor around the vehicle when parked
- No direct engine performance issues
Common Causes of Code P0455
Faults that trigger this code typically include:
- Cause 1: Loose, cracked, or missing gas cap (most common)
- Cause 2: Faulty EVAP Purge Valve or Vent Valve
- Cause 3: Cracked charcoal canister or damaged EVAP hoses
- Cause 4: Leaking fuel filler neck seal
Can you drive with a P0455 code?
Yes, it is safe to drive. The EVAP system prevents fuel vapors from escaping into the atmosphere. A leak will not affect engine performance, but it is an environmental concern and will prevent you from passing emissions tests.
Expected Repair Cost Band
A new gas cap costs $10 - $30. EVAP purge or vent valves cost $80 - $200. Replacing charcoal canisters or major EVAP lines ranges from $200 to $600.
Related Diagnostic Trouble Codes
If you have scanned multiple codes, see these related guides for troubleshooting context:
Frequently Asked Questions
It means the system detected a large opening (usually larger than 0.09 inches) that prevents the fuel tank from holding a vacuum.
Yes, a loose, damaged, or unclicked gas cap is the single most common cause of a gross EVAP leak.
No, it will not affect engine fuel consumption or performance, but you will lose tiny amounts of fuel to evaporation.
You can clear it using OBDAssistant after tightening your gas cap or replacing a faulty vent valve.
It is the Evaporative Emission Control system, which traps and recirculates fuel vapors from the gas tank so they aren't released into the air.