| Feature | Details |
|---|---|
| DTC Code | P1457 |
| Primary System | EVAP (Evaporative Emission Control System) |
| Most Common Vehicle | Honda / Acura (Civic, Accord, CR-V, Pilot) |
| Technical Definition | EVAP Control System Leakage (EVAP Canister System) |
If you own a Honda or Acura and your Check Engine Light is on with code P1457, you are dealing with one of the most common, yet annoying, issues in modern vehicles: an EVAP system leak.
Unlike diesel codes like P1453 or P1454 which affect engine performance, P1457 is purely an emissions issue. It means fuel vapors that should be trapped are leaking into the atmosphere.
The Crucial Difference: P1456 vs. P1457
Many car owners get confused because these two codes seem identical. In our previous guide on Code P1456, we explained that for Hondas, P1456 is usually a "Fuel Tank Side" leak—often just a loose gas cap.
P1457 is different. It specifically refers to a leak on the "Canister Side" of the system. This means tightening your gas cap will not fix a P1457 code.
Top 3 Causes of Code P1457
The EVAP system uses a "Charcoal Canister" to absorb fuel vapors like a sponge. When the engine runs, it opens valves to suck those vapors into the engine to be burned. P1457 means this part of the system isn't holding vacuum.
- Faulty CVS (Canister Vent Shut) Valve (Most Common): This valve is often located under the car near the rear axle, exposed to rain, salt, and mud. It frequently rusts internally and gets stuck open, preventing the system from sealing.
- Cracked or Rotted Vacuum Hoses: The rubber tubes connecting the canister to the engine engine become brittle over time and develop small cracks that leak air.
- Saturated Charcoal Canister: If you habitually "top off" your gas tank after the pump clicks off, liquid raw fuel can enter the charcoal canister, ruining it.
🔧 Professional Diagnosis (Bi-Directional Test)
Finding a P1457 leak without the right tools is difficult because the leak is often tiny. Mechanics use "Smoke Machines" to find them.
However, before paying for a smoke test, you can use an advanced diagnostic tool like the iCarsoft CR Ultra P to perform a Bi-Directional EVAP Test.
This function allows you to manually command the Vent Valve (CVS) to close while listening for the "click." If the scanner says it's commanded closed, but air still flows through it, you have confirmed a bad valve without guessing.
Can I drive with P1457?
Yes. P1457 will not damage your engine or affect drivability. However, your vehicle will fail an emissions inspection (smog check), and you may notice a faint smell of raw gasoline near the car on hot days.
Frequently Asked Questions
Will a new gas cap fix P1457?
No. A gas cap fixes code P1456. Code P1457 indicates the leak is elsewhere in the system, usually near the charcoal canister.
How much does it cost to fix P1457 on a Honda?
If it is the common Canister Vent Shut valve, the part is usually $50-$100. Labor can be 1-2 hours depending on how rusted the bolts are under the vehicle.
