VREF 0.3V 🤕

[JAS1445]

New to the Forums not to Fords lol

2011 Ranger 4.0

So i built this truck from the ground up.
After it was fully done i got these codes for TPS and DPFE, and figured out the ref voltage was apx 0.3 volts. I removed both pigtails as theyre both pcm supplied vref related and checked to be sure of no others are on the circuit.
Back probed the pcm and confirmed 0.30 volts apx.
Replaced the pcm and still have the same thing happening.

I then decided to go out on a limb and disconnect he FTP sensor and like magic i got my 5vref back from the pcm.

Now why is the ftp sensor dragging the pcm vref down...?
I pulled the plug at the sensor and im getting apx 4.3v at ftpref and apx 4.3v at ftp, the signal return is 0.0v
I pulled all three wire from the pcm pigtail and back probed the pigtail, confirmed apx 4.3v at the ftpref and apx 4.3v at FTP.

Its to my understanding that there should only be 1 reference voltage wire for the ftp sensor, the FTPREF (5v), the signal return should be no voltage, and FTP as called via the pcm would be pcm supplied ground. Is this correct?

Any help at all is appreciated as i dont know what to do at this point.

 

[scotts90ranger]

It sounds like the FTP is bad if it is pulling the voltage that far down, normally the reference voltage on stuff is closer to 5V than 4.3V though so maybe it's a bad voltage to the ECM?

 

[JAS1445]

i have the connector disconnected and the 3 wires removed from the pcm. i back probed all 3 pins at the pcm, two of the pcm pins are putting out that 4.3v, thats why im so confused... theres nothing hooked up..

Im thinking ill have to put each pin, 1 by 1 at a time to see if something else is causing the pcm to output 4.3 at TPS pinout on the pcm as i believe koeo it should be 0.0

 

[JAS1445]

actually, would someone be able to confirm that its supposed to be 2 powers and 1 open going to the FTP sensor or 1 power, 1 pcm supplied ground, and 1 open return?

 

[scotts90ranger]

A standard pressure sensor would be power, ground and signal but I had to look up what a FTP was since all my junk is older

 

[JAS1445]

haha, yeah, i think they started those sensor in 02 but dont hold me to it.

Ive disconnected the first pcm connector and back probed, and the third pcm connector and back probed and im still get power power open. All three wire are removed from that second pcm connector.

So maybe something on that second pcm connector is back feeding into the pcm or its supposed to be that way.

All i need is a confirmation on a truck 07 to 11 at the ftps that it is open ground and power. unfortunately for me i dont have another truck at those years disposable to me at the moment.

 

[JAS1445]

anybody, please??

 

[JAS1445]

bump

 

[pjtoledo]

is this what your ftps looks like?

Amazon.com: Motorcraft - Sensor Asy (P) (CX2380) : Automotive

 

[JAS1445]

No, it looks like this, mounted inline with vapor hoses, in frame above left rear wheel.
I believe this is 07 to 11 only.

Amazon.com

 

[JAS1445]

Someone please take 10 minutes to help me out, need on vehicle diag truck years 07-11.
Ill have to go to a junkyard otherwise

 

[lil_Blue_Ford]

I’m going to move this over to the engine forum. Might get a better response than the truck builds section…

 

[Uncle Gump]

Unless you have the internals for the PCM... STOP back probing the PCM. It's only confusing you.

The FTPS works similar to a MAP sensor. A peizeoelectric chip gets deflected based on pressure changes in the EVAP system. Three wires... Vref... Signal... sensor ground or low ref. Without knowing how the signal circuit is monitored you have no idea what you should see at the PCM when back probing the signal with the sensor disconnected. Signals are monitored though a voltage divider network and either pulled up or pulled down for the PCM to see the signal value.

It sounds to me that if the 5volt reference is nearly zero with the sensor connected... that sensor is internally shorted.

 

[pjtoledo]

you need access to a Powertrain Control/Emissions Diagnostic manual for your year.
the FTPS listed is also found on a 2002-2010 Explorer.

since the part is listed for 2002-2010 Explorer I feel safe using this manual.

sorry 'bout the toes, it's before noon

hang on, I lost the pin designations,,,,,

 

[pjtoledo]

found 'em

does this match up with your sensor?