P0455
Low SeverityEVAP System Large Leak Detected
EVAP System
P0455 — Instant Answer
EVAP System Large Leak Detected
Severity: LOW SEVERITY
Meaning: A significant leak in the EVAP system. Often a loose gas cap or a disconnected hose.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $5 - $50
Most common causes:
- 1. Loose or missing gas cap (35-45% of cases)
- 2. Disconnected EVAP hose (10-25% of cases)
- 3. Cracked canister or hose (10-25% of cases)
- 4. Failed purge or vent valve stuck open (10-25% of cases)
Symptoms
- ⚠️Check engine light
- ⚠️Possible fuel smell
- ⚠️Failed emissions
Related Symptoms
Common Causes
How to Diagnose P0455
- 1Check gas cap — tighten or replace
- 2Visual inspection of all EVAP hoses
- 3Smoke test EVAP system if cap is OK
- 4Check purge and vent valve operation
OEM Procedures for P0455
P0455 affects the Charcoal Canister. Found 2 OEM service manual procedures.
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
Charcoal Canister - Replacement (ES300)
OEM Diagnostic Flowchart
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Parts & Tools for This Job
Common parts shoppers buy for P0455 EVAP System Large Leak Detected.
Oxygen Sensor
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Catalytic Converter
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EVAP Purge Valve
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Gas Cap
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OBD2 scanner
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Check SpecificationsBattery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Check SpecificationsMultimeter kit
Confirm voltage, continuity, and sensor power with one simple kit.
A meter is the cheapest way to rule out a bad circuit fast.
Check SpecificationsRelated Resources
Repair guides, symptom pages, and wiring diagrams related to P0455.
OEM Manual Evidence
Browse →Mil Comes On With DTC P0455 And/Or P0456 (14-006) — 2013 Acura ILX Base, 2.0L Eng VIN 1 Service Manual ~ LEMON Manuals LEMON Manuals: Repai...
Mil Comes On With DTC P0455 And/Or P0456 (14-006) — 2013 Acura ILX Base, 2.0L Eng VIN 1 Service Manual ~ LEMON Manuals LEMON Manuals: Repai...
Mil Comes On With DTC P0455 And/Or P0456 (14-006) — 2013 Acura ILX Base, 2.0L Eng VIN 1 Service Manual ~ LEMON Manuals LEMON Manuals: Repai...
Mil Comes On With DTC P0455 And/Or P0456 (14-006) — 2013 Acura ILX Base, 2.0L Eng VIN 1 Service Manual ~ LEMON Manuals LEMON Manuals: Repai...
Related Symptoms
Browse →Related Codes
General EVAP system fault — the system that captures fuel vapors is not working properly.
A small leak in the EVAP system, often a deteriorated gas cap seal or a tiny crack in a hose.
A very small leak in the EVAP system — smaller than P0442.
Frequently Asked Questions
- Is P0455 the gas cap code?
- Most often yes. A loose, cracked, or missing gas cap is the #1 cause of P0455.
- How long after tightening the cap does the code clear?
- The code clears after 2-3 drive cycles (cold start, warm up, highway driving) if the leak is fixed.
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Author & Review
Published by AllOEMManuals, founded by Lyndon Bedford, an automotive technician with 20 years of experience. He owned and operated a mechanic shop in Hurst, Texas from 2014 to 2022 and continues hands-on repair work.
Content may combine manual references, general repair templates, and AI-assisted drafting. Confirm the source, vehicle configuration, and applicability before working. Report corrections through our contact page.
Last updated: 2026-11-07