P0451 Code
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5 Year Member
Joined: Mar 2019
Posts: 26
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From: Maine
What they did on mine was use their finger 👉 in and out through the flap quickly about 30 times. Yes, that is exactly what it sounds like, finger bang the fuel fill. Sorry to be vulgar.
Senior Member
Joined: Mar 2021
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For the 451 code, go back and read reply #6.
It's a Ford discerption.
For code 496, it is EVAP flow rate is too high. That is a pressure leak out or vacuum leak into the EVAP system at some point.
The Purge valve is Pulsed opens and pulls vacuum to check for leaks in either direction.
When truck is off, and goes into sleep mode, the. system is still monitored by the PCM for the same failure by looking at the Tank Pressure sensor for changes out of limits.
You can see how both codes could apply to the same or multiple faults.
Good luck.
It's a Ford discerption.
For code 496, it is EVAP flow rate is too high. That is a pressure leak out or vacuum leak into the EVAP system at some point.
The Purge valve is Pulsed opens and pulls vacuum to check for leaks in either direction.
When truck is off, and goes into sleep mode, the. system is still monitored by the PCM for the same failure by looking at the Tank Pressure sensor for changes out of limits.
You can see how both codes could apply to the same or multiple faults.
Good luck.
Member
Joined: Aug 2020
Posts: 69
Likes: 30
From: Salt Lake City, UT
If the EVAP system is working normally, will the fuel tank will be in a negative pressure state after a short drive on the freeway (cold day too)?
I am pulling a P0451 and P0496 CEL.
When I push the flap in with my finger, there seems to be significant negative pressure, I would say less than (as in more negative) -1.7” W.C. Not sure how to get a manometer on it, lol.
I’ve check the wiring for what I am assuming is the charcoal canister and pressure solenoid under the driver side frame. It seems fine.
I’ve never noticed this until I put gas in the tank a day after my CDF drum was replaced in the trans. I’d take it back but it’s inconvenient for me if it’s something simple I can fix myself. I’ll try the finger banging method in the interim.
TIA,
I am pulling a P0451 and P0496 CEL.
When I push the flap in with my finger, there seems to be significant negative pressure, I would say less than (as in more negative) -1.7” W.C. Not sure how to get a manometer on it, lol.
I’ve check the wiring for what I am assuming is the charcoal canister and pressure solenoid under the driver side frame. It seems fine.
I’ve never noticed this until I put gas in the tank a day after my CDF drum was replaced in the trans. I’d take it back but it’s inconvenient for me if it’s something simple I can fix myself. I’ll try the finger banging method in the interim.
TIA,
Last edited by NIMTZ; May 18, 2025 at 11:25 AM.
Senior Member
Joined: Mar 2021
Posts: 4,789
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Member
Joined: Aug 2020
Posts: 69
Likes: 30
From: Salt Lake City, UT
@Bluegrass where is the FTP reading viewable, FORscan? Thank you!
Where is the FTP sensor and where is the pressure controlling solenoid location? I would like to check them. I’m guessing the pressure sensor would be on the top of the tank. Hopefully Ford is smart enough to make a part like that serviceable.
Where is the FTP sensor and where is the pressure controlling solenoid location? I would like to check them. I’m guessing the pressure sensor would be on the top of the tank. Hopefully Ford is smart enough to make a part like that serviceable.
Last edited by NIMTZ; May 18, 2025 at 03:43 PM.