Ram-specific code — factory diagnostic data| DTC Data Sheet | |
| Code | P0455 |
| Vehicle | Ram 1500 (2009-2024) |
| Engine | All gasoline |
| System | EMISSION SYSTEM |
| Fault type | Leak |
| Official meaning | Evaporative Emission System Large Leak Detected |
Definition source: Ram factory description. Diagnostic guidance is based on factory-defined fault logic for this code.
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Looking for the cross-vehicle definition? Read the generic P0455 article for the SAE-defined fault logic that applies to all manufacturers.
P0455 Quick Answer
P0455 on a Ram 1500 means the EVAP system can’t hold any vacuum. The #1 cause is the gas cap — Ram trucks (especially 2013+ with capless fueling on some trims) frequently throw P0455 from a poorly-seated cap or a damaged capless fueling neck. #2 cause is cracked EVAP hoses near the canister; #3 is the canister vent solenoid stuck open. Most fixes are under $100.
What Does P0455 Mean on a Ram 1500?
The Ram 1500 (2009-2024) stores P0455 when the condition described above is met. This guide focuses on the All gasoline — the most common Ram 1500 powertrain. The platform-specific failure patterns documented below differ from the generic SAE definition.
Symptoms
- Check Engine Light (P0455)
- No driveability impact
- Possible fuel smell near rear of truck after refueling
- OBD-II inspection failure
- No fuel economy effect
Common Causes (Most Likely on This Model First)
- Loose or worn fuel cap. Tighten to 3 clicks. Replace cap if gasket is hardened or cracked.
- Damaged capless fueling neck (2013+ select trims). Ram’s capless fueling system on later trucks has a check valve in the neck. Misfueling debris, ice, or rough handling damages the seal. Inspect with a flashlight.
- Cracked EVAP hose. Plastic quick-connects near the canister (frame-mounted, under the bed). Cold climates crack the fittings.
- Canister vent solenoid stuck open. Dust and debris in the vent — especially on Rams driven off-pavement.
- Cracked EVAP canister. Impact damage from off-road use.
Diagnostic Approach
- Tighten cap to 3 clicks (or check capless neck on capless-equipped trucks). Clear code, drive 50+ miles.
- If P0455 returns, inspect cap gasket or capless check valve.
- Smoke-test from EVAP service port. Watch for smoke at canister, hoses, vent solenoid.
- Bidirectional command the canister vent solenoid; watch tank pressure.
- Inspect EVAP canister body under the bed for impact damage.
Possible Fixes
| Fix | When |
|---|---|
| Tighten or replace fuel cap | Start here |
| Capless neck repair / replacement | Capless system damaged |
| EVAP hose repair | Smoke at hose joint |
| Canister vent solenoid | Vent contaminated, won’t seal |
| EVAP canister replacement | Canister body damaged |
Can I Still Drive With P0455?
Yes — no driveability or safety impact. Defer indefinitely from a mechanical standpoint. Inspection states force the issue.
How Serious Is This Code?
Low. Cosmetic / regulatory.
Repair Costs
| Repair | Cost |
|---|---|
| Fuel cap | $15 – $40 |
| Capless neck assembly | $220 – $440 |
| EVAP hose | $40 – $180 |
| Canister vent solenoid | $80 – $180 |
| EVAP canister | $140 – $320 |
FAQ
How do I fix P0455 on a Ram 1500?
Start with the fuel cap (or capless fueling neck on later trucks). About 60-70% of Ram P0455 cases are cap-related. If a new cap doesn’t fix it, smoke-test the EVAP plumbing under the truck for hose leaks.
My Ram 1500 has capless fueling — what does that mean for P0455?
The capless system on 2013+ select Ram trims has a spring-loaded check valve in the filler neck instead of a removable cap. Damage to that check valve (from misfueling debris, ice, or rough handling) causes P0455. Inspect with a flashlight; replacement of the capless assembly runs $220-$440.
Does P0455 affect Ram fuel economy?
No. P0455 is a vapor-containment fault, not a fuel-delivery fault. Engine operation and fuel economy are unaffected.
How much to fix P0455 on a Ram 1500?
Fuel cap: $15-$40. Capless neck (later trucks): $220-$440. EVAP hose: $40-$180. Vent solenoid: $80-$180. Most P0455 fixes are under $100 unless the capless assembly is damaged.