P0456 code and leaky check valve?

LHC30

TJ Enthusiast
Original poster
Supporting Member
Joined
Jan 7, 2019
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188
Location
Lebanon, TN 37087
Searching the long start and p0456 code posts I don’t see the answer to my question - which is: will a leaking FP check valve cause a P0456 code to set?

my CEL started to light up about the time it began to take a few extra cycles to light off when cold. I have done Jerry Bransford’s “cycle the key prior to starting” and that does make a bit of difference. I have also checked the purge valve and canister hoses/connections in the engine bay ( I have an ‘01).

thanks for the insight folks.
 
Hiya Ted! It sounds like two unrelated issues. On the slow start, does that happen even after just stopping to refill the tank with gas, or only after it sits for a while, like overnight? The former is usually caused by a bad fuel pressure regulator. The latter usually from a bad fuel pump.

The P0456 can be any kind of an vacuum leak from a loose or leaky gas cap (or if the gas cap was off when starting it) to a split hose. They can be tough to find but a smoke generator from an auto parts store can really help locate the leak.

I hope you and Mimi are well! 😊
 
Thanks Jerry. We are well and as of the 11th, are grandparents!

I was hoping one fix would cure both symptoms but that is hoping for much. Lol
 
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