Check engine light DTC code P1456

Tiny
MMADDOX
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  • HONDA ODYSSEY
My van is a 2000 with a 3.5 liter V-Tec engine. The check engine light came on. I used an OBD2 scanner tool and retrieved code P1456, which my service manual shows as "EVAP system leak detected (fuel tank)." I have since replaced the fuel cap, making sure to twist it three or four clicks, and then erased the code. The check engine light came on during the next couple of trips, and my scanner later showed the same code. What tests would you recommend next in order to isolate the problem? What is the likely culprit?
Saturday, April 28th, 2007 AT 3:09 PM

8 Replies

Tiny
BRUCE HUNT
  • MECHANIC
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When you fill at a station does the nozzle often click off early or prematurely? I suspect a ventilation problem.
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Monday, April 30th, 2007 AT 4:40 PM
Tiny
MMADDOX
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No, the nozzle does not click off early or prematurely when I fill at a station. Any other ideas as to what the problem might be? Thanks.
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Monday, April 30th, 2007 AT 5:50 PM
Tiny
BRUCE HUNT
  • MECHANIC
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Try these tips:

Fuel filler cap, vacuum connection, fuel tank, fuel tank pressure sensor, evaporator bypass solenoid, evaporator two way valve, evaporator control canister vent shut valve, evaporator control canister and evaporator purge control solenoid. You have to understand that computer codes rarely define the exact component that has failed. All the computer code tells you is that a system that could have one component or many is not operating within the acceptable parameters of the computer's program. Code P1456 means that your vehicle is failing to contain/hold the gas vapors in the gas tank. Retrieving the code in your case was the easy part. If you are lucky it will be simply a replacement gas cap. If it is more than that, you will need to have the problem diagnosed. Because of the complexity of the system, it may take a couple of hours and some specialized equipment to diagnose the cause. You want to be sure the right part is being replaced because some of the components listed are pricey and you do not want to be replacing them on a guess. It would be great if the computer could make a little red flag pop up from the defective component. But then I would have less gray hair and be out a job if that were the case.
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Tuesday, May 1st, 2007 AT 7:45 AM
Tiny
CRIT21
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It is most likely your gas cap. It is either loose or missing. Our 1999 Civic had the same problem. My Passat also had a trouble code for the same thing. When you tighten the cap, you should make it click at least three times.
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Wednesday, April 30th, 2008 AT 11:57 AM
Tiny
DAK
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My wife's 2001 Odyssey threw a check engine light when I was traveling on business. I asked her to take it to the dealer and $105.00 later the code was translated to her as a loose gas cap. The dealer cleared the code and before I got home from my trip the light came back on. When I returned home I used some silicone grease to lube the gasket on the fuel cap and after a few days, the light turned off on its own. I just bought an Actron 9180 OBD2 scanner and found the P1456 in the system. I cleared it using the tool.
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Thursday, September 4th, 2008 AT 11:56 PM
Tiny
ANDAGOL
  • MEMBER
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Hi guys,

Actually, in my case the nozzle very often clicks off early.
I have got the engine light on about four month ago (I have Mitsubishi Lancer 2004). I have checked it at the dealership four or five times. They replaced a fuel cap, but it helped for a couple of days only. The engine light is again on.

Could you help me with this problem, please?
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Tuesday, March 24th, 2009 AT 6:43 PM
Tiny
DENARMST53
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I have the similar issue but have replaced the cap and tighten three clicks. One thing I have noticed is that the 1456 code is triggered when the gas tank falls below half. As long as I keep it at three quarter filled no code is triggered. This is very puzzling to me. I have also noticed that the evaporator purge control solenoid is always clicking and I am wondering if this is normal?
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Wednesday, October 19th, 2011 AT 5:05 PM
Tiny
KEN L
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Hey Denarmst53,

It sounds like the pressure sensor in the tank is bad and needs to be replaced.

Please let us know what you find so it will help others.

Best, Ken
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Tuesday, November 29th, 2016 AT 11:47 AM

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