P0440
Low SeverityEVAP System Malfunction
EVAP System
P0440 — Instant Answer
EVAP System Malfunction
Severity: LOW SEVERITY
Meaning: General EVAP system fault — the system that captures fuel vapors is not working properly.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $5 - $15
Most common causes:
- 1. Loose or cracked gas cap (35-45% of cases)
- 2. EVAP canister purge valve fault (10-25% of cases)
- 3. EVAP vent valve fault (10-25% of cases)
- 4. Cracked EVAP hose (10-25% of cases)
Symptoms
- ⚠️Check engine light
- ⚠️Faint fuel smell possible
- ⚠️Failed emissions test
Related Symptoms
Common Causes
How to Diagnose P0440
- 1Tighten gas cap and clear code
- 2If code returns, inspect gas cap seal
- 3Check purge and vent valves
- 4Smoke test EVAP system
OEM Procedures for P0440
P0440 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)
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Repair guides, symptom pages, and wiring diagrams related to P0440.
Related Codes
The EVAP purge flow is not within expected range.
A small leak in the EVAP system, often a deteriorated gas cap seal or a tiny crack in a hose.
A significant leak in the EVAP system. Often a loose gas cap or a disconnected hose.
Frequently Asked Questions
- What is the EVAP system?
- The EVAP system captures fuel vapors from the tank and routes them to the engine to be burned, preventing pollution.
- Can a loose gas cap cause P0440?
- Yes — the #1 cause of EVAP codes is a loose, cracked, or missing gas cap. Tighten it and clear the code.
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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