Interesting. Have you experienced any faults related to your PCM, Jeff? Was this replacement purely for pre-emptive purposes? At ~$1200 for the replacement PCM, it's not an insignificant investment. However, based on age and mileage, my '05 may be worthy of a similar upgrade.
I am researching options for correcting/calibrating my speedometer in my '05 LJ-R. Looks like the best option is an intermediate signal processor from Dakota Digital. I will contact Mark at WranglerFix and see if they can update the PCM to make this change internally. Rubicons use a tone wheel and H-E sensor for speed on the T-Case, not the old gear driven sending unit.
I've had no issues with the original PCM, buying the new one is a preemptive move. I did it for several reasons:
1. If one fails on the trail (or the road) I have a spare. Apparently failures aren't too uncommon, especially at high mileage and high temperatures, according to Mark at Wranglerfix. He had one opened at the show and I saw how they fail. It's not pretty.
2. Some PCMs are out of stock at MOPAR for extended periods of time. I wouldn't want my LJ to be out of commission for months waiting for a PCM from Jeep (of course I could buy one from Wranglerfix, but if the failure is in Colorado, what will I do with a dead Jeep in Colorado until a factory PCM or a Wranglerfix PCM could arrive?
3. The Wranglerfix PCM is apparently from a later model MOPAR vehicle and allegedly more reliable. (I suspect it's from a 3.7 liter Liberty or Cherokee, both of which I believe came out well after the TJ did).
4. According to Mark, the 4.0 runs better on the Wranglerfix PCM than it does on the factory PCM. Maybe that's marketing hype, I don't know.
5. He cut me a deal for less than $1000. Not sure if he does that for everyone or if I'm special.
On a related note, I talked to the lead Jeep tech at the local dealer, who has become a good friend, and asked him to make a list of electrical/electronic items he thinks would be good to have on hand in case they get discontinued. For example, the crankshaft position sensor. They're available aftermarket but he says some of those have fitment issues. Since I plan to have my '06's for a long time, I'm going to buy the parts on the list he makes for me to have on hand in case they become unavailable.