You might want to invest in a service manual, either hardcopy or DVD.
Here's one guy selling the DVD.
http://forums.corvetteforum.com/show...service+manual

U1255 The BCM and EBTCM did not receive info from the PCM.

Try disconnecting the harness that was causing the relay to chatter/buzz, and see if PCM comm is
restored.

I know you said you checked the grounds, but did you open them up and look inside, as shown in the following link.? You mentioned you were working on the front end of the car. You didn't inadvertantly disconnect one of the grounds while you were doing other repairs?
http://forums.corvetteforum.com/show...ighlight=u1255

Also check the data star connectors 1 ond 2 for a bad connection.

While the problem your seeing doesn't look like it's being caused by a shorted wire in the door, that has caused some weird problems in the past, and is fairly common problem, and easily tested. Wiggle the harness around where it comes through the drivers door and see if the symptoms change.

Taken from the manual:

Condition to set the DTC
* The BCM didn't receive a state of health (SOH) from the PCM when the ignition was first turned on.
* The BCM detected an open or short( to ground or voltage ) on the serial data line circuit.

Action taken when DTC sets
*U1255 stored in BCM memory
*The PCM will not allow fuel enable processing to occur. (cranks but won't run)
* No driver warning massage displayed on the DIC.
*BCM may substitute default values for certain systems

Diagnostic Aids
*If the U1255 is stored in the BCM and other systems capable of storing that code, check for a short to ground or voltage on that serial data line.
*If other systems do not have the same code, check for an open in the serial data line between the BCM and PCM or IPC (instrument panel cluster)

 

Yes it is a maggie car (supercharged).

I bought the 1998 service manuals awhile back when i began work on the car. But its like reading another language at times ha. I get the gist of what its telling me to do but not always to the point.

The grounds are where they should be bolted down and clean inside and out. checked and double checked that one.

Data star connections? Are these the two bulk connectors plugged into the pcm?

I recieved the u1255 code from multiple sources.

Riddle me this one... The battery neg wire that grounds to the engine block also has two smaller wires grounding at that location. Who knows what wires they are? I do believe i have found my problem they were both seperated how it happened... act of god?

 

Data star connectors Passenger footwell near the BCM

Did the ground wire fix your problem? If that was the wire to ground G104 that wasn't connected, it goes to splice pack 208 which provides grounds for numerous components, including the data link connector, instrument cluster and BCM along with other things. Refer to Vol 3 Ground Distribution Schematic Cell 14, page 8-441 in my '99 manual. Yours may be different. Also, the data star connector info is in the very front of volume 3.

 

not sure if its going to fix it or not as it is a "you know what" to get to and repair it o boy. lol goin out there now to see what i can do. i might have to pull the starter out but that looks like a job in itself. Ill post back if i get it tonight

 

You need to get a hold of a service manual brother, or your going to be chasing your tail.

 

Qoute from above.... I bought the 1998 service manuals awhile back when i began work on the car.

Alright the snow has hit and im going out plowing so what i found in the meantime.

When connecting the wires together and turning the key to the on position the relay stops its erratic nosies and and the fuel pumps prime!!! That could have been the best noise i have ever heard ha

Did not get a chance to run the codes or to actually fix that wire yet so sunday ill get out there and actually test everything.

Thanks for all your help! Hey greg you from aorund chicago? I feel i need to buy you a beer or seomthing you have been a great help to a newbie like myself.

 

It would help if you would fill out your sig, there is a lot of knowledge/help here in chicago

 

Problem solved! Car just fired up but i forgot the radiator is not in and trans fluid is now all over the garage floor... so I went out and began to fix that wire and noticed that the jacket was melted to the harness. So i thought it could be melted in side also so i opened up the harness and sure enough it was melted all the way to almost to the pcm. I found the splice pack in the main harness going to the pcm and routed two new grounds to replace that single wire one to the original location and one to the ground lug under the battery on the frame rail. I did that because that wire was obviously overloaded or somethin else is going on to over heat that wire like that. So maybe with that extra wire the problem is solved for good! i will just have to keep tabs on that wire and periodically check it to see if it is hot. But that splice had like 7 wires coming out of it if i remember right all a smaller gauge which leads me to believe the one I repaired was the only one that was "grounded"

but now the question is can you get the wire loom tape from gm? I did not open it completely just here and there to follow the wire to its destination. So to do this right i would like to close it back up like i was never there.

 

Just wrap it it up some 3m or other quality electrical tape. If you have headers you might want to some heat wrap stuff around the wires so they won't melt again.

 

That will probably be the first and only time you'll be mopping up trans fluid with a smile on your face.
It takes alot of current to get that wire hot enough to melt the insulation. Hopefully that hasn't stressed the circuitry in the PCM. When you get it back together, I would check to be sure those wires aren't getting warm. The burnt wire might be the result of the problem, not the cause. Hopefully everything is OK. I hope some of the info I sent was useful, or at least got you thinking about the possible solution to the problem.
It sounds like you will be starting the new year off right. Now get that bad boy finished up. It will be springtime before you know it.

 

I was thinking about that also. Were the melted wires close to the header?

 

Where the wire came out of the loom it was sorta close but not like right next to it. And the jacket was melted inside the harness over by the battery so its just kinda weird but it fired up lol

 

Just for safety get some Heat shild tape and put it around the loom where it is close. I purchased the heat shield tape from autozone.