P0455 on Buick
Evaporative Emission Control System Leak Detected (Gross Leak)
P0455 on Buick vehicles indicates evaporative emission control system leak detected (gross leak). Au7o has documented this code across 1 Buick model — most commonly on Encore. 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.
Common Causes of P0455
- •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
P0455 on Buick by Model
Buick Encore(1 issue)
- EVAP Purge Valve May Not Fully Close (Special Coverage N232395300)2020
GM Special Coverage N232395300 identifies certain 2020 Buick Encore vehicles with the 1.4L LUV engine whose evaporative-emissions purge valve may not fully close. The engine can run rough, hesitate or stall at idle, the check-engine light can illuminate and an EVAP or fuel-trim DTC can set.
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View P0455 across all makes →Frequently Asked Questions
What does P0455 mean on Buick?▼
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 Buick specifically, this code is documented across 1 model.
What causes P0455 on Buick vehicles?▼
Common causes on Buick: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0455 on a Buick?▼
Repair costs vary widely depending on the root cause and specific Buick model.
Which Buick models have P0455 documented?▼
Au7o has documented P0455 on 1 Buick model: Encore.