Well, I've got a brick of a PCM. I had a 10 minute window last night to try adjusting the speedometer. It failed at about 15K during the write and I have not been able to to get it to take a program for either laptop now. I've tried a few copies of the stock tune from both computers and still fails at 15K giving the checksum error.

I went out and bought a battery charger this morning. The battery is now charged to 100%. Still no good. I've probably tried it somewhere around 35 to 40 times now.

I've pulled the radio fuse and the HVAC fuses. Where is this elusive BCM fuse???

One thing I should note is that I am running version 2.4 on my V2. I've tried updating the firmware, and unless there is some other way of doing it, the V8 software only detects the USB connection to the V2. It does the same thing on either laptop. Can someone just email the firmware and bootblock updates? Will that work?

Any other thoughts? I have a wideband O2 that I was planning to install in the blazer to see what I could do to improve the mileage. However, with as unreliable as this is turning out to be, I'm now thinking about just buying a PCM tuned by PCM4Less and leaving it. The only thing the V2 has done with 100% reliability is read codes. Rather expensive code reader. This is very frustrating to say the least.