P0455 Code: Meaning, Causes, and Symptoms | OBD2 Codes

P0455 – Evaporative Emission Control System Leak Detected Gross Leak

P0455: What does it mean?

The Code P0455 means that a gross leak is detected in the Evaporative Emission Control System(EVAP)

The EVAP is designed to prevent gasoline vapors in the fuel tank from leaking into the atmosphere. It is monitored by the Powertrain Control Module (PCM) and when the computer detects a large leak in EVAP, it will turn on the engine light and send the Code P0455.

Similar codes are P0442 and P0456, which are EVAP small and EVAP very small leak detected. Click the hyperlinks to know more about the three codes.

Severity: Low

Although it’s said to be a gross leak, you may not feel anything other than the check engine light. But it should be fixed before you go to any emission test as it will fail the test. 

Difficulty of diagnosis or repair: 2 out of 5

P0455 Possible Symptoms

P0455 is not always noticeable except the engine light/service engine soon warning light. Sometimes, you can smell gasoline fuel in the filler area or tank area. The fuel efficiency might be affected by this code. 

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Possible a noticeable fuel odor caused by the release of fuel vapors
  • Decreased fuel efficiency

P0455 Possible Causes

There are many possible causes for the code P0455, including:

  • Missing or loose fuel cap
  • Incorrect fuel filler cap used
  • Fuel filler cap remains open or fails to close
  • Foreign matter caught in fuel filler cap
  • EVAP canister or fuel tank leaks
  • EVAP system hose leaking
  • Fuel tank leaking

Possible Checks/Fixes you can do yourself

When you see a Diagnostic Trouble Code P0455, there are several checks you can do:

  1. Check the diagnostic trouble code from your OBD2 Scanner / Car Code Scanner and verify that it’s the only code present. If other codes are on the list, they should be checked first, as they might have caused the code P0455.
  2. If you have other codes such as P0441 or P0440, the issue might be a solenoid failure or a more complex system leak. Address these issues first.
  3. If Code P0455 is the only code present, check your gas cap to see if it’s open or loose. Tighten your gas cap and the code might be cleared. And this is why the Code P0455 is the most common diagnostic trouble code searched on google.
  4. After you tighten the gas cap, the engine light may turn off after several drive cycles. Or you can clear the code with your obd2 scanner and see if the code comes back after several drive cycles. Refer to this article about the drive cycle. It will be completed mostly after a normal day drive. 
  5. If the engine light doesn’t go off(or comes back again), inspect your gas cap for physical damage or deterioration. It’s not always noticeable, you can try to replace your gas cap as it’s not expensive. It usually will clear the codes P0455.
  6. If a replaced fuel cap didn’t fix it, you can check for aged, cracked or disconnected hoses of the EVAP near or connected to the engine air box. This is a common problem for old cars because of aged rubber hoses and dry-out gaskets. Replace the hoses and clear the code.
  7. If a replaced hose doesn’t solve the problem and the code comes back again, you should consider performing an EVAP system leak check. You can do it in most repair shops and car dealers. They will usually perform a smoke check through your EVAP and the smoke will show if there’s any leak from any hoses or seals.

How much is the cost to clear P0455?

For car code P0455, several repairs may apply, and the cost estimations are below:

  • Replace the Gas Cap: $20-$60
  • EVAP Line: $20-$100
  • EVAP Vent Control Valve: $150-$200
  • Purge Volume Control Valve: $150-$200

Frequently Asked Questions

Q: Can I drive with the code P0455?

A: You may drive your vehicle with Code P0455 unless you smell or see a serious fuel/liquid leak.