1998 PCM Swap Question

[capt_bob]

I am having problems with the OBD2 port on my 1998 4.0L OHV, 4x4, 5-spd XLT. The dealer wants to install a new PCM to fix it. I would like to save some money and install a used PCM from a junkyard. Can I use a PCM from a similarly equipped 1996/7 and bypass the whole PATS system and the need to have the PCM re-flashed at the dealer? Is there a site where I can download PCM harness wiring diagrams? Thanks for the help!

 

[410Fortune]

no
there are wiring changes in 98

What issues are you having with the OBD-II port? Is it not getting power?
If not then check your fuse for the cig lighter

 

[CDW6212R]

The PATSII and newer models have the PCM and pats module married together. Each is required or the vehicle will not start. The two units must be married(coded) to one another, by a Ford tool. Good luck,

 

[capt_bob]

My Explorer runs great and I do not have any problems with CEL. My problem is that I cannot access sensor data from the PCM. I bought a Carchip E/X and cannot download engine parameter values through my OBD2 port. I am getting power to the port (fuses are good) and the Carchip records the engine start and stop cycles. I cannot get engine parameters such as O2 sensor voltage, fuel trim, speed, distance etc from my OBD2 port. The values all come up as zeros. I tested the Carchip on a 2000 Ford Taurus and it worked fine and recorded all the data it was supposed to. The dealer is convinced it is a bad PCM. I am reluctant to spend almost $500 if I can pick up a used PCM for $30 at a local pick your parts.

 

[410Fortune]

Find a 98 truck like yours pull the computer, pats module, key, and cable
Swap them to your truck.