P0442 on GMC: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Small Leak)
1 GMC model · 1 documented issue
P0442 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)
P0442 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 P0442 mean on a GMC?
P0442 stands for "Evaporative Emission Control System Leak Detected (Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it. On GMC it is documented across 1 model: Sierra 1500.
What are the most common causes of P0442?
The most common causes of P0442 are: Loose, damaged, or missing fuel filler cap, Worn or cracked gas cap seal, Cracked or disconnected EVAP hose or line, Faulty purge valve or vent valve, Damaged O-ring or seal at the fuel tank or filler neck, Small crack in the charcoal canister, Leaking fuel tank sending unit gasket. The specific cause varies by vehicle.
How much does it cost to fix P0442 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.