P0455 on a 2022 Ram 1500 Crew 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 Crew Cab

Ranked from 588 NHTSA owner complaints filed for this vehicle.

Sort by:

1
EVAP vent / fuel-tank valve failure
Medium severity
Dealer identified the fuel tank's EVAP vent valve as faulty (broken fill-side nipple) after the truck refused to accept fuel, calling it a common issue on these trucks -- a stuck vent path can produce a large-leak fault.
Reported in 1 NHTSA complaint
Parts:fuel tank vent valve
2
EVAP system leak reported alongside fuel-pump fault
Low severity
Owner's check-engine light was tied to a documented emissions-system leak noted alongside an unrelated fuel-pump fault.
Reported in 1 NHTSA complaint
3
Loose, damaged, or missing gas cap
Low severity
The single most common cause of a large-leak EVAP code.
Common cause
Parts:gas cap
4
Cracked or disconnected EVAP line
Medium severity
A fully detached or split line produces a large-leak code quickly.
Common cause
5
Purge valve stuck open
Medium severity
A purge valve stuck open prevents the system from holding vacuum during the monitor.
Common cause
Parts:purge valve
6
Charcoal canister crack
Low severity
A cracked canister housing is a common large-leak source.
Common cause
Parts:charcoal canister
7
Rusted/corroded fuel filler neck
Medium severity
Perforation near the cap seat is common on higher-mileage trucks.
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