Causes and Fixes Honda P1456 Error Code

By | July 11, 2023

Honda P1456

If you have a Honda with a P1456 error code, the onboard computer (ECM) is seeing an error with the Evap system.

The official definition for a Honda P1456 is EVAP Control System Leak Detected (Fuel Tank System).

The Evap system helps a vehicle run more efficiently and reduce emissions.

When the system is not working correctly, a P1456 error code is given.

The most common cause is a loose or bad gas cap.

What Is a Honda P1456 Code?

A Honda P1456 Code OBDII code is an “EVAP Control System Leak Detected (Fuel Tank System).”

The EVAP system takes gas vapors from the gas tank and feeds them into the engine to be burnt away.

The onboard computer (ECM) is seeing a leak in the system which will need to be found to fix the problem.

Causes can include a gas cap, leaking hose, blown fuse, wiring, solenoid, or bad vent valve (Shut Valve CVS).

Honda P1456 Code Symptoms

  • Engine Light On
  • Not Able to Pass a Smog Test

What Causes a Honda P1456 Code?

  • Bad Gas Cap
  • Evap Leak
  • Blown Fuse
  • Bad Vent Valve (Shut Valve CVS)
  • Bad Purge Valve
  • Bad Charcoal Canister
  • Bad Fuel Tank Pressure Sensor

A loose or bad gas cap is the most common fix for a P1456 error code.
Causes and Fixes Honda P1456 Error Code Gas Cap
The gas cap has a seal that allows fumes that usually would be vented to go back into the engine to be brunt.

This gives the vehicle better fuel efficiency and less emissions.

When the system is not sealed, it will not work properly and give the P1456 error code.

Often a new gas cap will fix the problem; simply be sure it is an original Honda cap as some alternatives do not work correctly.

A problem with the vent valve, sometimes called a Shut Valve, can also cause the problem.
Causes and Fixes Honda P1456 Error Code Purge Valve
The vent valve stores the gas vapors and is located near the gas tank.

A blown fuse can cause the vent valve to not work and should be checked and tested.

A bad wire or connection or a leak in the EVAP system can also cause a P1456 code.

How To Fix a Honda with a P1456 Code

  • Be sure the gas cap is on the vehicle and screwed on tightly.
  • Check the gas cap, and if bad, replace it.
  • Check and test all your fuses and replace any bad ones if found.
  • Check the vent valve and replace if bad.
  • Check the Charcoal Canister and replace if bad.
  • Check for leaks in the system.

Cost To Diagnose and Repair a Honda with P1456 Code

The cost to troubleshoot a P1456 Code will depend on the cause of the problem.

Most mechanics will first replace the gas cap, which is a simple fix and does not cost too much.

If the vent valve is bad or wiring, more time will be needed to find and fix the problem, which will cost more.

A Honda P1456 Code is usually not an expensive repair with the usually fix a new gas cap.

If there is a wiring problem or a leak in the system, it can take more time to find and fix, which can run up the hours for a repair.

How Serious is a Honda with a P1456 Code?

A P1456 code is not a serious issue and is an EVAP error related to smog controls.

The vehicle will not be able to pass a smog test and will need to be fixed first.

The vehicle should drive fine until it can be repaired.

Have you had issues with a Honda P1456 OBDII code? Let us know your thoughts below.

Bob Thomas
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