Wascoman63

I found some good info on YouTube. "Class 2 Data" refers to GMs network protocol for communication between the various "modules" of the vehicle. Each module is a dedicated computer that must communicate with every other module (powertrain, body, doors, AC, antilock brakes, etc.). They are all interconnected by a single wire that shares data between the modules. This system is set up to operate on 7 volts, so any higher or lower voltage would indicate that one of the modules is failing - or else there is a problem somewhere along the wire. If any module is dumping the wrong voltage into the system things can go south in a hurry. If you want to know more, I recommend a video by a fellow named "Rico L" that is titled "GM Class 2 Data Line Diagnosis and Repair Info". He does an excellent job of explaining how this all works. Evidently there is a device under the dash called a "Splice Pack" where wires from all of the modules come together. They are inter-connected at the splice pack with a device called a "comb". If you remove the comb you can check the voltage on each of the modules. I haven't done any more yet and probably won't for a few days as I have family visiting.

Well, my buddy brought his full-fledged scan tool over. The scanner kept saying that it could not communicate with the ECU. Consistently returned a "Class 2 Data Link Malfunction U1000". Our guess is that the issue is not in the computer but somewhere in the bus where all of the communications between the various modules takes place. We checked all of the wires going into the ECU and none are rodent damaged; we check each fuse in both fuse boxes; and we briefly disconnected the Mass Air Sensor to make sure that it wasn't gumming up the works. So, now I think that we know that it isn't the theft deterrent system. The vehicle will fire and run each and every time you turn the key, but it runs for just an instant before it shuts off. My mechanic thinks that the reason that it shuts off is that the computer is not receiving any information and therefore it shuts everything down. Don't know where to turn next.

I am in Oregon. I do not have a fancy scan tool but my local mechanic does and he has agreed to do a housecall and bring his scan tool along (I buy him breakfast sometimes). Will let you know what we find.

I tried this suggestion today - no luck. On another forum someone suggested that my ignition key or my ignition key module may be "worn". Don't know what that means but any opinions are appreciated.

I have owned a 2006 Silverado 1500 for a couple of months. Installed a new battery about a month ago. Everything was working fine until I went away for a week. Now the truck will not start - it fires and runs for about 1 second and then shuts off. I've tried all all of the YouTube video fixes, talked to the local GM dealer, dis-connected and re-connected the battery, put a charger on the battery to make sure that it was fully charged - but nothing has worked. When I first turn the key to on, the theft deterrent light is not on. When I try to start it the theft deterrent light comes on immediately, the truck fires and them immediately dies. Sometimes, when I turn the key to the on position without starting the truck, the theft deterrent light comes on for less than a minute, then it goes out. If I try to start the truck the theft deterrent light comes back on and stays on. The theft deterrent light is either off or on - at no time does it flash. I'm at my wit's end. Can any one help?