Causes and Fixes Honda P1456 Error Code

By | August 31, 2022

Causes and Fixes Honda P1456 Error Code
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.

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

When the system has 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.”

Some scan tools will also give an “Emission Control System Leak Detected (Fuel Tank System).”

The onboard computer (ECM) is not able to communicate with the purge solenoid.

Causes can include a blown fuse, wiring, gas cap, solenoid, or bad purge valve.

Honda P1456 Code Symptoms

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

What Causes a Honda P1456 Code?

  • Bad Gas Cap
  • Fuse
  • Purge Valve Wiring
  • Bad Purge Valve
  • Charcoal Canister
  • Evap Leak

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 purge valve can also cause the problem.
Causes and Fixes Honda P1456 Error Code Purge Valve
The purge valve is closed when the engine is not running and opens when the engine is on to allow fumes to be burnt away.

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

A bad wire or connection can also cause the purge valve to not work correctly.

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 all the wiring going to the purge valve and test for voltage on the positive wire.
  • Check the purge valve and replace if bad.
  • Check the Charcoal Canister and replace if bad.
  • Check for leak in 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 purge 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, this 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 car should drive fine until it can be repaired.

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

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