P0456
Low SeverityEVAP System Very Small Leak Detected
EVAP System
P0456 — Instant Answer
EVAP System Very Small Leak Detected
Severity: LOW SEVERITY
Meaning: A very small leak in the EVAP system — smaller than P0442.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $5 - $15
Most common causes:
- 1. Aging gas cap seal (35-45% of cases)
- 2. Tiny crack in EVAP hose (10-25% of cases)
- 3. Micro-crack in canister (5-10% of cases)
Common Causes
How to Diagnose P0456
- 1Replace gas cap first
- 2Smoke test if cap replacement does not fix it
- 3Inspect all hose connections closely
OEM Procedures for P0456
P0456 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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Repair guides, symptom pages, and wiring diagrams related to P0456.
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
A significant leak in the EVAP system. Often a loose gas cap or a disconnected hose.
A small leak in the EVAP system, often a deteriorated gas cap seal or a tiny crack in a hose.
General EVAP system fault — the system that captures fuel vapors is not working properly.
Frequently Asked Questions
- Is P0456 hard to find?
- Very small leaks can be difficult to find. A professional-grade smoke test machine is often needed.
- Can temperature changes cause P0456?
- Cold weather can temporarily trigger EVAP codes as seals contract. If it only appears in winter, the gas cap seal may be marginal.
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Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07