Error Code P0451

[KillerPenz]

Original Code: P0496

Add this to my list of growing codes involving the EVAP system.

Made about 1,000 miles from clearing the code to getting a new code. Unless anyone has any thoughts on these 2, looks like I'll be making an appointment to have Ford check it out. Still haven't got around to replacing purge valve, but this new code seems to list purge valve way down the list.

Code: P0451 - EVAP System Pressure Sensor/Switch 'A' Circuit Range/Performance



Status (-ED):

- DTC Present at Time of Request

- Malfunction Indicator Lamp is On for this DTC

- Test not complete



Module: Powertrain Control Module



Freeze Frame #1:



Freeze Frame #2:

-EVENT_TIME: 125933684 s (Fri Oct 17 15:31:29 2025) - Event time

-TOTAL_DISTANCE: 96921 miles - Total Distance

-FUELSYS: Open Loop - Fuel System Status (Open/Closed Loop)

-LOAD: 57.25 % - Calculated Load Value

-ECT: 73 °F - Engine coolant temperature

-ECT: 73 °F - Engine coolant temperature

-SHRTFT1: 0.00 % - Short term fuel trim 1

-LONGFT1: -4.69 % - Long term fuel trim 1

-SHRTFT2: 0.00 % - Short term fuel trim 2

-LONGFT2: -1.56 % - Long term fuel trim 2

-MAP: 9.1 psi - Manifold absolute pressure sensor

-RPM: 1290 1/min - Engine Revolutions Per Minute

-VSS: 0.0 mph - Vehicle Speed

-VSS: 0.0 mph - Vehicle Speed

-SPARKADV: -13.00 ° - Spark Advance

-IAT: 72 °F - Intake Air Temperature

-RUNTM: 2 s - Time Since Engine Start

-RUNTM: 2 s - Engine Run Time

-FRP: 1232.8 psi - Fuel Rail Pressure

-EVAP_PCT: 0.00 % - Commanded Evaporative Purge

-FLI: 65.88 % - Fuel Level

-BARO: 14.6 psi - Barometric pressure

-BARO: 14.6 psi - Barometric pressure

-VPWR: 13.58 V - Control Module Voltage

-VPWR: 13.58 V - Control Module Voltage

-TP_REL: 8.63 % - Relative Throttle Position

-TAC_PCT: 18.04 % - Commanded Throttle Actuator Control

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[Bschurr]

Well that sux! I had a buddy that had that happen on his Maverick and he used the white plastic funnel in the cargo area and jammed it in the fuel filler a few times and after a few start/stop cycles the code cleared… YMMV

 

[KillerPenz]

Well that sux! I had a buddy that had that happen on his Maverick and he used the white plastic funnel in the cargo area and jammed it in the fuel filler a few times and after a few start/stop cycles the code cleared… YMMV

I did read that somewhere. Funny thing is, it happened like 20 miles after filling up the tank. And when you combine it with the other code I got a few weeks back, I figure something stupid is going on.

 

[Dan-O]

I’ve had this happen on an F-150 I owned and a buddy’s Mercedes did the same thing. Both popped an Evap code shortly after getting gas…..in both situations we topped off the tank. Codes cleared short time later. I chalked it up to fuel getting in the vent line and some making it to the evap canister. Ive never Topped fuel tank off on any vehicle since.

 

[KillerPenz]

I’ve had this happen on an F-150 I owned and a buddy’s Mercedes did the same thing. Both popped an Evap code shortly after getting gas…..in both situations we topped off the tank. Codes cleared short time later. I chalked it up to fuel getting in the vent line and some making it to the evap canister. Ive never Topped fuel tank off on any vehicle since.

I wish that were the case for me. Here in NJ it's "illegal" to pump our own gas. Doesn't meant we don't do it, but some places get upset if we do... Which so happens to be the place I go to, so tank not topped off.

But...the odd thing is, I went 1,000 miles between the 2 codes I got. And since resetting, probably put on a couple hundred more miles without any codes. It's one of those things that I'll monitor and see where I end up.

 

[rblume73]

It's a fuel tank pressure too low code. I have it on my F-150, and it requires changing out the fuel pressure sensor on the tank, which is part of the whole fuel line assembly for my truck. I would take it in if it's still under warranty. A clogged vent canister could cause it also, since it can't relieve vacuum on the tank. Let us know how it goes?

 

[KillerPenz]

It's a fuel tank pressure too low code. I have it on my F-150, and it requires changing out the fuel pressure sensor on the tank, which is part of the whole fuel line assembly for my truck. I would take it in if it's still under warranty. A clogged vent canister could cause it also, since it can't relieve vacuum on the tank. Let us know how it goes?

Unfortunately, not even close to being under warranty, 97k miles. Was figuring it was going to need to be brought to a dealer or mechanic. Just depends on how much I want to bent over at this point. Thanks for the info.

 

[Ducati1098]

Most likely still the purge valve. I would guess the only reason it's throwing this code is because the vacuum on the fuel tank is so high that the FTP sensor is out of range (which is basically all this new code means)
Or the FTP sensor is actually bad, which could have caused the first code. That's just far less likely.

Regardless, without a way to monitor live data, you'll just be guessing.

 

[KillerPenz]

Most likely still the purge valve. I would guess the only reason it's throwing this code is because the vacuum on the fuel tank is so high that the FTP sensor is out of range (which is basically all this new code means)
Or the FTP sensor is actually bad, which could have caused the first code. That's just far less likely.

Regardless, without a way to monitor live data, you'll just be guessing.

Definitely over here guessing. Maybe this weekend I'll replace the purge valve and see where that gets me. At least that is easy enough to get to.

 

[KillerPenz]

Update: Replaced the purge valve, doesn't seem to be what the issue is. Starting to think this is pointing towards the pressure sensor on the tank as I've cleared the code, it came back in a day. Used the white filler neck and no luck so far. Going to take it in to a local shop let them do the smoke test and figure it out from here.

@Ducati1098 do you know the part number for the pressure sensor?

 

[Ducati1098]

Update: Replaced the purge valve, doesn't seem to be what the issue is. Starting to think this is pointing towards the pressure sensor on the tank as I've cleared the code, it came back in a day. Used the white filler neck and no luck so far. Going to take it in to a local shop let them do the smoke test and figure it out from here.

@Ducati1098 do you know the part number for the pressure sensor?

Send me your VIN

 

[KillerPenz]

Well that sux! I had a buddy that had that happen on his Maverick and he used the white plastic funnel in the cargo area and jammed it in the fuel filler a few times and after a few start/stop cycles the code cleared… YMMV

OK, so I've cleared the code twice this week, each time code came back same day. Last night I used the plastic funnel, but left the code in there. Drove to work and back (75 miles round trip), still had the light. Picked wife up from work tonight (her Jeep being worked on... no surprise there ), still had the code. Drove out to Pa to get dinner, no more check engine light. Came home, still no light. So I guess now we see how long the check engine light stays off.

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