Accessing the PCM on my 2002 8.1 2500.....

[ramyankee]

I guess it is under the battery. Is it simpler to access it from above or below?

[shakazulu12]

I had one of his tunes on my Avalanche with the 8.1. LOVED it. Couldn't believe how much power was being dialed out with torque management. I did a few things to the trans to beef it up a bit. Never missed a beat. I specifically asked for a tune optimized for 87 pump and had no regrets. I'm sure I left some power on the table, but didn't want the expense of premium.

[cruise-ader]

Justin at blackbear has a tremendous reputation in the performance tuning community.
Let us know how you like the tune!

[PaulJ2]

As with most of these I would expect a better spark advance curve and probably premium fuel required. Would also like to know how it works out.

[ramyankee]

Yes, what he will do is send out a OBD box (think that is the correct name). This process must be done with a laptop. You will download drivers from EFILive. You connect this OBD to the laptop, choose parameters, go for a drive, 20ish minutes. Save the file. Send it to him. He then builds a personalized tuning for your truck.....Then he will send your PCM to you. You may have to go through a security process and a crank re-learn.....Hopefully it will be a good way to go. Not what I would call expensive.

[BurbMan]

Nice! Let me know how that works out. Do you have to send your PCM to get reprogrammed or do you swap in a new one and send yours back as a core?

[ramyankee]

I have contacted Justin at Blackbear Performance and am dropping in a small tuning package.....30hp-40hp to maybe 50#ft of torque.

[BurbMan]

Just curious why are you taking it out? Did it fail?

[PaulJ2]

On my 2004 8.1 it is located on the left side of the radiator panel under a plastic cover, part of the fan shroud.

[ramyankee]

But do you need to remove the battery? I am sure that is easier and sure will not harm anything.....

[N-Trouble]

Not sure on the 8.1 but on my old 6.0 it was on the drives side behind the battery just above the inner wheel well. You access it from the top. It is inside a black plastic enclosure about the size of a lunch pale. Open the enclosure and you will see the PCM with a wire harness coming out the side. THe harness is removed with a couple of ~10mm bolts and the PCM slides out. Be sure to disconnect the battery ahead of time.