Dazed and Confused
Join Date: May 2012
Location: Upstate New York
Re: 2004 Freestar no communication
Ok, I'm trying to piece this together without a schematic and after reading over both posts, I'm wondering if you're looking at this backwards. The pressure sensor is pretty much a transducer. One wire is always hot, one wire is ground and the third is your varying signal.
If they're calling the wire your on a reference signal, that may be your hot wire. I would verify your tank is really not pressurizing, and that your carbon canister and vent line aren't plugged. If the vent line is clear, pull it from your canister and try running it again and see if the diagnostic clears, then put it back on the canister, if it comes back, you may need a new canister.
Ever notice that there's so many high performance parts available for GM products?
Did you ever think that maybe they NEED them?