TDIDog

Where is it on a 2004 Freestar? Is it on the tank or is it on the Evap canister? I looked at Tousley Ford online parts and I didn't find it and the Parts chica at the local dealer didn't find it either. Maybe it's part of another valve on the tank?

R.S.LOGAN

" 2004 ford freestar fuel tank pressure sensor. It's above the gas tank, so u have to drop the gas tank down and remove it. As you can see its attached to the main evap line. I couldn't find it at Any auto parts store had to go to te dealer ship an it's a couple of hundreds "

TDIDog

Ugh. Thanks. I am getting a P0452 code which has to do with reading too high of a voltage on one of the wires, so the Vref voltage is shorting to the other wire, either in a wire or in the sensor. Now that i know where it is and about how much it will cost, I can make a decision on how to approach it. Thank you very much.

R.S.LOGAN

Glad to help .Awkward to get at and pricy too .

TDIDog

Yeah, it's the awkward to get at part that I am thinking of. I have dropped the tank before - it's a wheelchair conversion so it mounted mid-ship - so I'm sure that I would have to get a brand new one and cut it up so that sucks too, but I was thinking of having one here just in case it's bad but now I need to rethink that strategy.

TDIDog

So I'm digging into this thing trying to figure it out. What I'm finding is that my scanner is showing 5.12 volts on the signal from the FTP sensor. This is causing the P0453 code which is Vref shorted to signal. I pulled the connector to the fuel tank harness and I still get the 5.12 V on the FTP (V) PID. This should isolate the problem as something other than the sensor.

So then I need to figure out how to isolate other parts of the circuit. According to my wiring diagram, the Vref wire goes to the BEC and that is where I get lost. The BEC is the fuse panel under the hood and all I see in there is fuse connections, but what I am looking for is a bus connection with 12 wires connected to it. Is this buried in the BEC, or is it someplace else and I just have a crappy wiring diagram?

TDIDog

This is what I get in the troubleshooter on our Solus Pro scanner:

Continuous DTC P0453 indicates fuel tank pressure circuit input above minimum.

P0453 may set anytime PCM detects high voltage in fuel tank pressure circuit. PCM Monitors FTP input signal to PCM. Code sets when signal average jumps above a minimum allowable parameter.

Possible causes are:
FTP sensor open or shorted to VREF, SIG RTN shorted to VPWR, damaged FTP sensor or faulty PCM.

So, doesn't unplugging the fuel tank harness eliminate problems with the FTP sensor?

I will try to post some PDFs of the wiring circuit.

TDIDog

OK, so it won't allow me to post a PDF...

CatSkinner

Never messed with fuel tank pressure sensor, but I've dealt with similar technologies elsewhere. Usually a 0 psi signal still sends some sort of a signal, so if the controlling device doesn't see any signal at all, it'll still throw a code. Can't see why it would be different on a car.

__________________
Prius repellant, just add gas.

TDIDog

The thing is, the scanner is telling me that it's an electrical issue with the VPWR shorted to Signal. It shows the signal voltage as 5.12 which is what VPWR would be and it shows this with the sensor harness unplugged and the signal wire pulled from the PCM connector.