P0455 on a 2022 Ram 1500 Quad Cab

P0455 means the EVAP system failed a leak check badly enough that the computer sees a large leak or no pressure/vacuum change.

Not your vehicle? See general P0455 info.

Most common causes on the 2022 Ram 1500 Quad Cab

Ranked from 588 NHTSA owner complaints filed for this vehicle.

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1
Fuel tank vent/fill valve failure
High severity
One owner's tank-mounted EVAP valve wouldn't let the tank vent while fueling, described as a widely-reported defect on this truck; a valve that fails to seat is a large enough opening to trip the large-leak EVAP threshold.
Reported in 1 NHTSA complaint
Parts:fuel tank vent valve
2
Degraded EVAP hose or seal near the fuel pump module
Medium severity
One truck threw a check-engine light for a small emissions-system leak at the same time its fuel pump was failing, consistent with a worn seal or hose in the shared fuel/EVAP module that can widen into a large leak.
Reported in 1 NHTSA complaint
Parts:EVAP hose
3
Loose or damaged gas cap
Medium severity
A cap that isn't sealing, has a worn gasket, or is missing is the single most common cause of a large EVAP leak code.
Common cause
Parts:fuel cap
4
Cracked or disconnected EVAP canister or hose
Medium severity
A split hose or cracked canister housing creates a large enough opening to fail the leak-detection test outright.
Common cause
Parts:charcoal canister EVAP hose
5
Purge valve stuck open
Medium severity
A purge valve stuck fully open provides a wide-open path between the intake and the fuel tank, registering as a large leak.
Common cause
Parts:purge valve
6
Fuel tank or filler neck corrosion/rust-through
Medium severity
Corrosion can perforate the tank or filler neck, creating a large, constant vapor leak.
Common cause

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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0455 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Fuel smell
Usually no performance issue
Failed emissions readiness

What to check before replacing parts

Check the gas cap first

Look for: A loose, missing, or cross-threaded cap is by far the most common cause of a large EVAP leak code — if it doesn't click to full tightness or the seal is cracked, that's very likely the whole fault.

Inspect visible EVAP hoses

Look for: A large leak is often obvious: a hose disconnected at a fitting, split open, or chewed through (rodent damage is common) rather than a hairline crack.

Command the purge and vent valves with a scan tool

Look for: A valve that doesn't respond at all when commanded open/closed, or stays open when it should seal, prevents the system from holding pressure/vacuum and reads as a large leak.

Smoke-test the system

Look for: With a large leak, expect an obvious plume of smoke or a clearly audible hiss at the fault location — it should be easy to spot compared to a small-leak diagnosis.

Inspect the canister and filler neck

Look for: A cracked charcoal canister housing or a corroded/rusted-through filler neck (common on older vehicles) can leak enough to prevent the system from ever holding vacuum.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light