P0455 on Porsche: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Gross Leak)
1 Porsche model · 1 documented issue · 1 critical
P0455 on Porsche by model: symptoms, diagnosis and fix
Porsche recall ALA2 / NHTSA 20V077 covers 70,117 potentially affected 2015-2018 Macan variants. Under load, the fuel-pump service cover can contact the flow nozzle on the filter flange; over time the nozzle can develop hairline cracks that permit fuel seepage and odor. Fuel leakage near an ignition source increases fire risk. Not every 2015-2018 Macan is included, so check your VIN.
Common Symptoms
- Fuel odor in or around the vehicle
- Fuel seepage
How to Fix
Check the VIN for open campaign ALA2 and arrange the free Porsche recall remedy. The dealer removes and reworks or replaces the service cover, inspects the filter-flange supply port, replaces a cracked flange and applies the specified protective film when required. If fuel odor or wetness is present, avoid ignition sources and have the vehicle inspected rather than attempting a retail-parts repair. Campaign status and the authorized VIN-specific remedy determine the repair, so do not buy a fuel pump, flange, cover or film yourself.
Sources for this issue (2)
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 Porsche?
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 Porsche it is documented across 1 model: Macan.
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 Porsche?
Repair costs vary widely with the root cause and Porsche 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.