P0455

What This Code Means

Code P0455 points to a large leak in the evaporative emissions (EVAP) system. The EVAP system captures fuel vapor from the gas tank and routes it to the intake manifold to be burned. When this code sets, the system cannot establish the required vacuum, which means a significant breach somewhere in the loop. The most common cause is a loose or faulty gas cap. Other possibilities: cracked EVAP hoses or a bad purge valve at the charcoal canister.

Symptoms

• Check Engine light is on
• Fuel smell around the car
• Possible refueling problems (pump nozzle shuts off early)

Diagnosis and Repair

Step 1: Check the Gas Cap

Make sure the gas cap is threaded on tight until it clicks. Inspect the O-ring for damage. Replace the cap if needed.

Step 2: Visual Inspection of the EVAP Hoses

Check every EVAP hose for cracks, splits, or disconnected fittings. Pay close attention to the connections at the charcoal canister and the purge valve.

Step 3: Test the Purge Valve

Check the canister purge valve (OEM 13901437480) for leaks and proper operation. Replace it if it fails.

Step 4: Smoke Test

To pinpoint the leak, use a smoke machine. Hook it up to the EVAP system and watch where the smoke escapes.

Related Problems

Ignoring the code can lead to rough running as unmetered air gets pulled in through the leak. The whole EVAP system can also fail, which means replacing the charcoal canister. In rare cases you'll see higher fuel consumption and worse emissions numbers.