P1456
EVAP Emission Control System Leakage (Fuel Tank Side)
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The P1456 code is Honda's manufacturer-specific code for an EVAP system leak detected on the fuel tank side of the system. The EVAP (Evaporative Emission Control) system captures fuel vapors from the gas tank and routes them to the engine to be burned, preventing them from escaping into the atmosphere. When the ECM runs its self-test and detects that the fuel tank side cannot hold pressure, it sets this code.
The good news is that P1456 usually doesn't affect how your car drives. You may not notice any symptoms at all beyond the Check Engine light. The most common cause — and the cheapest fix — is simply a loose or worn gas cap. Try tightening your gas cap until it clicks firmly, or replace it with a new one (typically $10–$20 for an OEM Honda cap). Clear the code and drive for a few days to see if it returns.
If a new gas cap doesn't resolve the code, the leak may be in the fuel filler neck or the EVAP hoses near the tank. A professional smoke test can pinpoint the exact location of the leak. While a gas cap replacement is a simple fix anyone can do, tracing and repairing other EVAP leaks may require lifting the vehicle and accessing components near the fuel tank, which is better suited for a shop with proper equipment.
Severity
Symptoms
- •Check Engine light illuminated
- •Faint fuel odor near the vehicle
- •Slightly reduced fuel economy
- •Failed emissions inspection
- •No noticeable drivability symptoms in most cases
- •Gas cap may feel loose or not click when tightened
Likely Causes
The most common cause is a gas cap that doesn't seal properly due to a cracked O-ring, cross-threading, or simply not being tightened until it clicks.
The metal or rubber fuel filler neck connecting the gas cap to the fuel tank can develop cracks or corrosion, allowing vapors to escape.
Small cracks, rust perforation, or failed seals on the fuel tank itself can create EVAP leaks on the tank side of the system.
Rubber EVAP hoses connecting the fuel tank to the charcoal canister can crack, disconnect, or deteriorate, creating vapor leaks.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the gas cap with a new OEM or quality aftermarket cap
- Inspect and replace cracked fuel filler neck
- Repair or replace damaged EVAP hoses near the fuel tank
- Perform a smoke test to locate the exact leak point