P0455 on RAM: How to Diagnose & Fix
Evaporative Emission Control System Leak Detected (Gross Leak)
1 RAM model · 1 documented issue · $30-$300 repair
P0455 on RAM by model: symptoms, diagnosis and fix
A very common check-engine complaint is EVAP 'small leak' codes P0456/P0442 (and sometimes P0455). On 2013-2020 trucks the usual culprits are the Evaporative System Integrity Monitor (ESIM) pump on the charcoal canister or a failed purge valve; on 2019+ capless-filler trucks the capless fuel-filler seal or the purge valve is the frequent cause. It won't harm the drivetrain but fails emissions testing and is a high-frequency search among owners.
Common Symptoms
- Check engine light
- P0456/P0442 stored codes
- No driveability change
- Occasional faint fuel smell
- Failed emissions/state inspection
How to Fix
Do not just clear the code — smoke-test the EVAP system to pinpoint the leak. Replace the ESIM (an inexpensive DIY on the canister) or the purge valve if it fails to hold vacuum, and inspect/replace the capless fuel-filler seal on 5th-gen trucks. Verify the gas cap/filler seals and check EVAP lines for cracks. Re-run the EVAP monitor to confirm the repair.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 04861959AD evaporative system integrity module
Live page is configured to a 2016 Ram 1500 Tradesman 5.7L and lists 04861959AD; confirm year, engine, canister design and VIN.
- Genuine Mopar 04627996AC vapor canister purge valve
2019-2021 Ram 1500 5.7L and 2019 Ram 1500 Classic 5.7L explicitly listed; confirm eTorque/non-eTorque configuration and VIN.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
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 RAM?
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 RAM it is documented across 1 model: 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 RAM?
Published repair estimates on RAM range from $30 to $300 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0455 on a different make?
View P0455 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.