Having problems with the PATS system on my truck. I've read thru about every post on the forum and am not finding exactly what's happening with my system nor a resolution. So let me start with this and see where I can get.
Been to the dealer, they cant communicate with the PCM. Says the PCM is bad 1600 to fix, Nope not happening so they say the can get it rebuilt, I mention the of the local company, they say yea that's where they would send it, ok, I'll take care of it myself. End result the repair facility say's the PCM is fine, nothing wrong with it after testing. Back to square 1. so here is what I see and have done up to this point
antitheft light flashes fast, after waiting for a few it flashes code 16, odometer reads ----------, OBD2 port not functioning, Fuel pump is turning on.
Checked the relays with one out of my other running truck, no change, Checked the fuses, found nothing blown. Used both key's removed all key fobs and other crap so only the key was there. No change
removed the Colum covers to access the key cylinder found nothing loose or damaged. started trouble shooting the wiring on the key cylinder by the Ford repair manual and have found nothing out of spec, 10.2v, all grounds good. tested continuity to the instrument cluster all good, Now the trouble shooting guide says replace the cluster, I'm not sure about that yet.
Anything I have not done that anyone can suggest? the OBD2 not working concerns me and found nothing on trouble shooting that?
Any help would be greatly appreciated, thanks

 

Check the cig lighter fuse. That protects the OBD2 port.

 

Checked that, all the fuses are good.

 

You have to have power at your port to talk to the pcm, I would fix that 1st....I thought the pats runs through the cluster on that year? I don't remember

 

Ok, I have power at the data port now. still can't talk to the PCM, Code reader will not connect. PATS code of 1-6

Ran the wiring harness yesterday (for most of the day). everything tested good in the wiring. had voltage were it was supposed to within spec and ohm'd out good on everything. now I'm at that point again. Any other ideas?

 

are they able to communicate with the Cluster? Any codes present?

 

Is the PCM the only module you cant communicate with? If thats the case and your wiring is good, power & ground is good at PCM then I would say you have a bad PCM.

 

Well according to the dealer they couldn't talk to anything thru the data port. the PCM was sent out for repair and they found nothing wrong with it.
all the wiring tests out good from the data port to everything, PCM, Cluster, PATS...

 

So how did you resolve this issue? (Your last post was almost 6 years ago.) I'm now having the same issue(s).
Thanks!!

 

I had a similar problem on an 2004 & replaced the ignition switch.

 

Im having pcm problems with my 04 lariat..CEL is on..brake light and abs light on,battery charge light on..speedo and tach not working..not communicating with obd2..truck runs drives in reduced power mode..

 

Replacing instrument clustet next week