Stalling

Hello, this code is for the Fuel "Tank" pressure sensor. I stress the tank part because some people get it confused with the fuel rail pressure sensor. And yes, it is part of the Evap system, these sensors are extremely sensitive, especially on ford setups. Ford has a completely different evap system and it runs its self-tests differently than any other manufacture. The sensor is located on top of the fuel tank, fortunately for you, you can remove the rear seat to get to it instead of dropping the tank. So, the code is for Sensor High Input, meaning the signal is sending to the ECM is higher than it should be. This can be caused by a number of things, bad ground, short to reference voltage etc. What I would do before you go taking the seat out, is when it stalls again. check the reference voltage at another sensor. The easiest place would be at the Fuel rail pressure sensor. Where the fuel injectors are. Ill post wiring diagrams, because if the reference voltage is being pulled down by a shorted sensor, you'll know right away which sensor it is and what's going on. It may be setting the code for the Tank pressure sensor because they are so sensitive. It would be the first sensor to have an odd signal. So, the first diagram is for the Fuel Rail Pressure sensor. and just make sure there's a full 5 volts on this wire with the key on. The last diagram is the Fuel Tank Pressure sensor. The yellow/blue wire is the 5-volt reference wire, the grey/red is the signal return (ground). and the red/pink wire is the signal back to the ECM. The Ford systems run a total of 4 or 5 tests on the evap system at various times, it has to pass the first 2 vacuum decay tests to go on to the Vapor Generation tests. So, it is pretty complicated. It took me awhile to learn it all honestly. But this could be a bad ground, missing 5 volts, or bad signal at the ECM, or just a bad sensor so you'll have to do some testing with a multimeter at the sensor to be sure. I will post more information here and if you have any questions on testing let us know.

The reason it's setting the codes every few drive cycles is because that's when it will be running its self-tests.
This code also be a Canister Vent valve or Purge valve that is stuck open and that's why it's stalling out. The main cause of this code on Pro Demand seems to be the wiring harness back at the sensor itself, so you will have to pull the rear seat eventually and check out the wiring harness. You can find the sensor by wiring colors for it.
And since you mentioned you have an mk800 you can start by actually checking the data PID for the sensor. anything over 4.5volts is a concern. Thats with the engine running.
Another real quick test is to disconnect the purge valve and block off the intake manifold line to it. If the stalling stops, you know you're getting flow when you shouldn't. The last diagram shows the purge valve wiring colors. It's located in the engine compartment.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

The barometric pressure is correct. The atmosphere is about 14PSI. So that's correct, the Evap system vapor pressure is measured in H20, (water) this is because it's a wider range of pressure to be monitored. 16 inH20 is about 0.5psi. So very low. Also, just FYI, if you go to take the Fuel Tank Pressure sensor out, make sure you don't have a full tank of gas.
So, is it not drivable now? Just start and stall? If that's the case, the first thing I would do is block off the purge valve from the intake manifold and see how it runs. I'm wondering if your charcoal canister is full of liquid gas instead of just fuel vapors.
The vehicle usually won't purge at cold start up, but all systems are different. While the system is purging the Evap it also opens the canister vent valve and draws a small amount of oxygen from the vent valve that mixes with the fuel vapors and then is pulled into the intake manifold. If the charcoal canister is full of liquid gas and pulling liquid gas into the intake due to a failed purge valve that could flood the engine right out. Maybe take a look at the sparkplugs and see if they're fouled out. I'm going to take a look through the TSBs for any information on Recall notices.

Going back to your previous post with the EVAP system vapor pressure dial reading, that's where that reading is coming from, The Fuel Tank Pressure sensor/transducer. Looking at it again, notice that it's in the orange range, almost red. I'd say that's where your fault comes from. You should be able to take the gas cap off and the pressure in the fuel tank should drop to 0 on your Scan tool. If the Tank Pressure sensor is reading higher than 0 you can release the pressure that way. If it doesn't drop to 0 there's a problem with it. It's on top of the gas tank.
If you look back up top, I put directions to get to it by removing the rear seat. It's a 3-wire sensor, so a Reference voltage wire (5 volts) yellow/light blue wire, a ground (grey/red wire) that's shared with the Mass Air Flow sensor and the APP sensor (Accelerator Pedal Position), and a Signal wire back to the ECM (red/pink wire).
So, you can check that it has its Ref voltage and its Ground. To be certain of the Signal wire is making it back to the ECM undisturbed you can check the voltage at the sensor and either compare that to scan data or go to the ECM and check the Pin there and see that the voltage reading is the same. But with a High Voltage code I would be concerned with bad ground or short to the signal wire. But do the gas cap test, it's probably just a bad sensor. These sensors are so sensitive, the expansion of the Fuel Vapors is actually measured with this sensor. That's just from the fuel vapors warming up. Thats what Fords Vapor Generation Test is, so it's the opposite of the vacuum test. But if you think about how low the pressure rise would be from just vapor expanding, it's such a small amount and that's why this sensor has to be reading in H20, to watch for such slight rises.

But that fault was the original code you had at the beginning of this. I'm a little surprised this is a no start condition. I don't think this would cause a no start condition. So, I would probably pull the rear seat and check the wiring harness back there. Maybe the harness is in trouble and the fuel pump is losing power or ground as well.

And that data, is that just Key On or is that Cranking? I'm also concerned with the Fuel Tank Pressure value is maxed out. Fuel pump command is off, is this still a no start, correct?

So, I'm assuming the 2-wire sensor you are seeing is the sending unit for the Fuel Gauge on the cluster. I see the 2 access holes, so the Fuel Tank Pressure Transducer is going to be through the passenger side access, it's going to be high up on the tank, so it avoids liquid gas. It may be attached to the Vapor line coming off the top of the tank, but it will be at one of the highest points, 3rd diagram is the connector. My biggest concern is that 4.99 voltage reading. That almost points to the Signal wire possibly being shorted to the 5-volt reference wire. And the no start issue might be another problem all together. Is this an Auction vehicle? With the start-stall issue, which sounds fuel related. Does this car have Dual Fuel injection? Two injectors per cylinder?
Another concern is that your Fuel pump Value is reading 75% but the Fuel Pump command is "off". There's more going on here, I think. This does have a Fuel Pump Module that is responsible for Fuel control. So, it's not directly the ECM.
After a stall out, what are your fuel trims reading? And are the 02s giving any reading at all. I know its in Open Loop, so the ECM is going to be looking at the Coolant Temperature for fuel control until it goes into Closed Loop operation.
But I think after we get this code issue figured out, there might still be a no start condition.

I fully agree with getting this right for him. With a half throttle response like that. Have you looked at the Mass Air flow sensor for any carbon build up? I'd check that since it's easy to get to, not sure if I mentioned that already, trying to go back through what we've looked at already. Unless the ECM is ruining the fuel injectors due to the high fuel tank pressure reading. I wonder what it would do if you left the fuel cap off and started it. Maybe the high-pressure reading is cutting off injector pulse for a safety reason. It's odd you can keep it running at part throttle. That sends my thinking into a whole different direction.

Okay, I just came across something. High positive crankcase pressure can set this code for some reason. Try popping the oil dipstick out and let it sit there. See if you're getting pressure blowing out that tube. I wonder if the PCV system is at fault here.

Also, if you can get to the Fuel Tank Pressure sensor, unplug it and recheck your reading on the scan tool. If it's still reading 5-volts. That needs to be addressed, because that will be a short to the signal wire, if it reads 5-volts it's a short to the Reference voltage.
Which is what it looks like, or a shorted sensor. But something else is happening here too.
We may need to unplug the ECM connector at some point if that high voltage reading won't go down. Because the ECMs code is correct, it's actually seeing high voltage. But with the way the PCV systems are built now, I don't disregard anything anymore.

Well, I'm not sure, from what I see there's 3 sub-models, Limited, SE, and SEL. But they all have the same engine. 3.0liter CD 991 engine. The Fuel tank pressure sensor might be on the very top where you just can't see it, I hope the Coolant sensor wasn't reading 173degrees C, that's 354 degrees F. So, we'll have to recheck that when you're feeling better. I'm sure this car has a tank pressure sensor, you have data pids reading pressure and codes for it. It's been part of Fords Evap systems forever.
You're only getting the P0453 correct? Maybe the coolant sensor is causing an intermittent issue. But get back to me when you're feeling better. I will be here. I think we need to run through all your live data PIDS and take an overall look at everything.

Okay, it will be over pressurizing at the oil spout. If the PCV is stuck closed. Hope you feel better.

Oh, wow what's the definition under Generator Monitor, what does that value mean? Its reading a fault, was there any code for the Alternator? I wonder if a diode failed inside the alternator and it's putting out ac voltage ripple. You can check that by setting your multimeter on ac volts, it will be a very low range (around 2-volt range). The Max ac voltage is only 50-75mv, so if the diode set or just one diode out of the 3 is bad it can send the ECM into a mess. It can't read ac voltage. Some alternators will still show a charging voltage but have failed diodes that can take out the ECM, it looks pretty unsteady, Id like to know what that value % means though, that little arrow next to it will have the definition of that parameter. I would think there would be a code too if the ECM is picking up a fault like that.
And you're correct, if there's some strange voltage issue going on who knows what codes it will throw out, I took a screen shot of your Scan tool. Looks like an Autel correct? Ill see if I have that data pid on mine. I know the car has a Fuel Tank Pressure sensor, but I would do the same you're doing and worry about a charging system issue first.

If you erase the code, just key "on" engine "off", and cycle the key. Does the code come right back without starting the engine? I remember the voltage on the tank reading 4.99-volts, which is as high as the sensor reading can go. I can't see the reading being just about 5-volts without the signal wire being shorted to the 5-V ref wire. That sensor would never really hit 5 volts at any time during normal operation. And you said you took off the gas cap and no change in that voltage signal if I remember correctly. If that's true, then it can't be an actual pressure too high issue. Try running the car for a while and keep those Evap data pids pulled up, like Purge, Vent Valve, Tank Pressure etc, and see if it changes at all during warm up or after a while of running. I'm going to look in some other places to see if I can find exactly where the sensor lives, It would really help if we could get it unplugged and see what it does to scan data.

Okay, I just went through an hours' worth of wiring diagrams, I found a connector C211 that has the Fuel Tank Pressure sensors 5vRef, Signal, and Ground, it's under the driver side dash. It's a bulk connector so I don't what else runs through it, ie, airbag wires and such,

So, I don't recommend pulling the connector apart, but you could back probe the connector and see what voltage readings you're getting there.

Another option is going right to the ECM connector C175B which I recommend this because it might be easier to get to and we know everything that's on that connector. You can even de-pin the signal wire or its reference voltage wire and see if one is shorted to the other. It looks like the pressure sensor doesn't share the Ref voltage with any other sensors. It does share a ground though.

So, I leave it up to you how you want to do this, but it's going to be much faster than trying to get to that sensor near the gas tank. Plus, I found that the Tank Pressure sensor can be an inline on the vapor hose, there's 2 different types.
So, I recommend going to the ECM and checking at the C175B connector, I will put everything you need for diagrams below. You can even check the Input Battery Voltage (hot at all times) on Pin #45.
I'm going to put the other connector that's under the driver side dash if you want to back-probe that connector too. Connector C211 (diagrams 3-5)
Diagram 6 is the 2 types of Tank Pressure sensors, probably why we can't find it under there. And finally pages 7 and 8 are everything on that ECM connector C175B so you know what you're disconnecting if you unplug it. I don't know if you need to disconnect the battery negative to unplug the ECM connectors on this vehicle, I would definitely have the key Off first. But at least you can get at these wires now.
I know that if you unplug the connector on a 3-wire component that uses a 5vRef you will read 5 volts on the signal wire because it's usually a bias voltage from the ECM to check the circuit integrity.

No, I think if you're really seeing a difference with temperature change and it's consistent then that's something to consider. You have a charging fault too. With heat related problems they come and go in a matter of minutes, so if we step back and look at everything together, you've got a charging system fault that the ECM is seeing, it's also seeing and evap system fault, a high pressure reading in the tank when there's no actual high pressure. Thats what we know. This can definitely be a pin-fitment issue at the ECM or one of those bulk connectors. Thats what I would be checking, and do it right where it all starts, the ECM connector. You don't need to get under the car for that and if you look at where that ECM connector is, the bottom of the windshield is the perfect place for it to get water intrusion.
Really, go check those connectors. That first picture shows the ECM connector being right under the windshield cowl.
This all points to a connection issue.

https://www.youtube.com/watch?v=IrDL810CEI4

Watch this video, this is what I'm talking about, faults with these fords and the wiring harnesses and connectors

https://www.youtube.com/watch?v=3jxtj0cI_AA

Here's another one, same exact problem, wiring harness issue, sitting on an A/C line and cutting through the harness.