I give up.

[WeathermanShawn]

Isn't Marcin (RedHardSupra) in Charleston, SC?

I don't know if he does trucks..but is there anything he doesn't know?

Isn't that just a few hours drive at most?

[ScarabEpic22]

Devil, try pulling the tune out of your Z06 and let us know. Since you can grab the TCM file from your truck Im thinking there's something wired to the ECM harness thats messing up your comms. Have you tried disconnecting your HU and any adapters it uses? Know its a pain, but even without fuses/power they can still mess stuff up. Ive spent 45+ min before on the side of the road trying to get a tune to flash back in.

[n8dogg]

I had a similar problem. I asked for help nicely and followed everyone suggestions. It was the firmware in my scan tool. Works perfect now!

[killerbee]

I suggested that you use a battery charger, while reading. Have you done that?

[joecar]

Devil_Z,

Do you have V7.5.6.125 and V8.1.2.105 installed...?

Did you flash 2.6.35 specifically from the V8.1.2.105 install...?


(there are several beta 2.6.35 firmware files... each time you install a new V8 software build you need to flash in the new 2.6.35)

[NMDuramax]

I had this same problem when I first tried to do my download. I have a 2005 LLY too and I learned that hard way after i tried several times to do the same thing you are. Neither EFI Live or the GM Tech II will do anything with the databus unless the "15 amp Radio" fuse is pulled under the hood on the drivers side with an aftermarket stereo that has its own bus. After I did that I have had no issues doing downloads or tunes as long as I pull that fuse.

[killerbee]

That is the power draw issue that is remedied with the battery charger. Which can also be caused by poor battery charge, hvac fan, etc.

[Racehemi]

I had some really weird issues on an LLY that once had a BullyDog tune installed.... sounds like you need to have someone with a TechII reflash it using a fresh calibration file. A Full Flash using the V2 may work also but you will need the stock tune.

[Cougar281]

I had this same problem when I first tried to do my download. I have a 2005 LLY too and I learned that hard way after i tried several times to do the same thing you are. Neither EFI Live or the GM Tech II will do anything with the databus unless the "15 amp Radio" fuse is pulled under the hood on the drivers side with an aftermarket stereo that has its own bus. After I did that I have had no issues doing downloads or tunes as long as I pull that fuse.

Is this a 2005 specific thing? I've never pulled any fuses at all in my 04 LLY (now LBZ) and I've never even had the slightest problem reading, flashing, etc with with my V1, V2 or Tech2.

[bballer182]

from what i've heard it kind of a hit n miss type of deal. some it's a problem and some it's not...