I have a 2008 F-150 and need to replace the pcm. I have found one with the same exactt part number on it. Will this used unit require a re programming before it will work in my truck?
Yes. Be sure your used pcm comes from a truck with the exact same drivetrain configuration as yours. Then find a mobile locksmith who can come to you and reprogram your anti-theft system so your truck will start.
@ddale
Question
How did you determine that the pcm needed to be replaced?
I am asking, because as a pro, there have been few instance, at least for me, where replacing the pcm was necessary
Wouldn’t a used pcm from another truck already be married to that particular truck?
In other words, how would you know it’s possible to remarry it to OP’s truck?
At the Benz dealer, you couldn’t take a pcm from a 2008 model year vehicle, and remarry it to an identical 2008 model year vehicle. There simply wasn’t any provision for it. The pcm would continue to look for the vin number of the original vehicle. And as such, you would have a no-start situation.
As far as I know Fords have no VIN mismatch issues for the pcm other than for the PATS system. Once you get the anti-theft learned it should be plug-n-play. But I suppose I could be wrong. Last Ford pcm I replaced was a 2006 model, didn’t need vin coding. I could look it up but I have some paying work to do. 
As far as I know Fords have no VIN mismatch issues for the pcm other than for the PATS system. Once you get the anti-theft learned it should be plug-n-play. But I suppose I could be wrong. Last Ford pcm I replaced was a 2006 model, didn’t need vin coding. I could look it up but I have some paying work to do.
That would be very fortunate for OP
As far as Benz goes, once you do the scn and cvn coding, the pcm is married to the vehicle . . . no divorce possible!
But, as I said, I haven’t replaced a pcm in 4 years, so I may be a little out of date
I just replaced the PCM on a neighbors 2005 Trail Blazer last week.
They turned the corner down the street and vehicle died. They knocked on my door and asked if I could find out what had happened as the vehicle wouldn’t start. As in nothing from the starter. So I grabbed my jump pack walked down the street and connected it to the battery. Still nothing from the starter.
So I came back and grabbed the scanner, and when I hooked it up to the vehicle there were six DTC listed. None of which had anything to do with the engine starting and running. That’s one clue that there’s a problem with the PCM.
So I came back and looked up the starting system on the vehicle. And lo and behold the PCM controlled the starter relay. So I got a used PCM from a local auto recycler, installed it, plugged it in and the engine started right up.
I also replaced the PCM in my son-in-laws Accura a few months back. In this case the PCM was no longer regulating the voltage from the generator so the battery kept dying.
In both cases it was a simple plug and play affair.
Here’s a picture of the defective PCM’s
Tester
You were fortunate
In some cases, it’s not simple plug and play. In some cases, it flat out won’t even work
I believe the reasoning is that you’ll have to buy the pcm from the dealer, versus going to the bone yard, as you did. I also think it has to do with theft protection. A pcm can potentially be pretty expensive. So, if a pcm is a paperweight in all vehicles except the one it came from, you’re supposedly less likely to steal it.
After I Installed the PCM in the Trail Blazer, I had to leave the ignition switch on for fifteen minutes so the PATS would recognize the ignition key. After that, it started.
Tester