I have a 01 honda accord 2.3l it has a obd fault code p1456, can any one tell me what this code means?

Code p1456 : EVAP Control System Leakage ( fuel tank system).

try check the fuel fill cap. It must be a gray or black OEM cap and be tightened at least 3" clicks" to properly seal the system.

Smal evap leak detected....very common check your fuel cap make sure it't tightened at least three clicks-check the o-ring of the cap as this will
cause a leak as well. drive vehicle the code will clear it's self if it odes not go away after 1 week of continuos driving it may have a larger leak
in this case you need to see a dealership-they will perform evap function test and determine if problem is worse-1457 is the bad one indicates large leak and can be expensive,. hope this helps.