EVAP Emission Control System Leakage (Fuel Tank System)

What it means

This is a Honda- and Acura-specific code; the same number can mean something different on other makes. The engine computer found a leak in the fuel tank side of the EVAP system: the tank, filler neck, fuel cap and nearby lines. It rarely affects how the engine runs, but it lets fuel vapor escape.

Models covered: Honda and Acura models, mainly around 1996–2010 (e.g. Accord, Civic, CR-V, Odyssey, Pilot).

Related codes: P1457P0455P0456P0442P0457

Symptoms3

• Check engine light on with no change in driving.
• Faint fuel smell near the filler area at times.
• Code appears soon after refueling if the cap was not closed properly.

Possible causes6

• Loose fuel cap, a worn cap seal or a non-matching cap.
• Rust or damage on the filler neck where the cap seals.
• Cracked or disconnected vapor hoses at the tank.
• Faulty two-way valve on the tank vapor line.
• Faulty fuel tank pressure sensor or its seal.
• Leak at the fuel pump module seal on top of the tank.

How to diagnose5

1. Check the fuel cap and seal, and tighten it until it clicks.
2. Inspect the filler neck lip for rust or scratches.
3. Have a smoke test done on the tank side of the system.
4. Watch the fuel tank pressure sensor reading with a scan tool during the system test.
5. Inspect the hoses and fittings above the tank and around the two-way valve.

How to fix5

1. Close the cap properly or replace it with a genuine matching cap.
2. Replace any cracked hose or fitting.
3. Replace the two-way valve or the tank pressure sensor based on the test result.
4. Replace the filler neck if it is corroded.
5. Clear the code and let the system retest over a few days of normal driving.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

Often the fix is simply a new fuel cap; the cost rises when a smoke test and a filler neck or parts on top of the tank are needed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions