P0455 on GMC: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Gross Leak)
1 GMC model · 2 documented issues
P0455 on GMC by model: symptoms, diagnosis and fix
GM says a strong fuel odor during fueling or at idle, with possible P0442 or P0455, may be caused by a fracture of the gasoline filler neck recirculation (vent) line connector. 2014-2015 GMC Sierra 1500 except Regular Cab, per GM bulletin 15-NA-019 (December 2015).
How to Fix
Have a technician raise the truck and inspect the fuel tank filler vent hose connector. Bulletin 15-NA-019 says to replace the fuel tank filler vent hose if the connector is damaged (GM part 22802073 is listed for 2013-2015 Sierra except Regular Cab) and to continue normal diagnosis if it is not. Normal warranty rules apply; this is not a recall or a promise of free repair.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (1)
GM says dirt, dust or water drawn into the EVAP canister vent solenoid (CVS) valve's fresh-air intake can restrict airflow or corrode the valve, turning on the check-engine light with P0442, P0446, P0455 or P0449 and making the fuel tank hard to fill. 2014 GMC Sierra 1500 and 2015 GMC Sierra, per GM bulletin 15-06-04-002 (April 2015).
How to Fix
Have a technician follow the service-manual EVAP diagnosis. If the CVS valve is the cause, bulletin 15-06-04-002 says to replace it with the revised sealed design that vents through a remote pre-filter on the fuel filler housing, and not to replace the EVAP canister unless it fails the leak test or has taken in excessive dirt, dust or water. Normal warranty rules apply; this is not a recall or a promise of free repair.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (1)
P0455 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0455 mean on a GMC?
P0455 stands for "Evaporative Emission Control System Leak Detected (Gross Leak)." This code means your car's evaporative emission (EVAP) system has detected a large (gross) leak, so fuel vapors that should be sealed inside the fuel and vapor system are escaping into the atmosphere. The EVAP system captures gasoline vapors from the tank and routes them to the engine to be burned instead of polluting the air, and the computer periodically pressure- or vacuum-tests this sealed system. A gross leak almost always points to something obvious and easy, like a loose, missing, or bad gas cap, rather than a deep mechanical failure. It rarely affects how the car drives, but it should be fixed to pass emissions and stop wasting fuel vapor. On GMC it is documented across 1 model: Sierra 1500.
What are the most common causes of P0455?
The most common causes of P0455 are: Loose, missing, or improperly tightened gas cap, Worn, cracked, or failed gas cap seal, Cracked or disconnected EVAP/vapor hose, Damaged or missing fuel filler neck seal, Faulty EVAP purge valve stuck open, Failed EVAP vent valve, Cracked or damaged charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0455 on a GMC?
Repair costs vary widely with the root cause and GMC model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.