Security issues - will not program

[nastynate98]

My truck is a 2001 2500HD 6.0 and it will start but then die 1 second later. Code P1626 Theft Deterrent Fuel Enable Lost. So the security system is shutting down the truck. I already tried the trick of unplugging the 3 prong pigtail by the key and connecting the left 2 wires together. But after I do this and turn the key ON, the security light does NOT flash, and therefore will not learn the new key code. It is only when I turn the key OFF that the security light would stay on solid.

 

So I did some more research and found out that the BCM could be bad. I tried to communicate with the current BCM and nothing. I pulled a BCM out of the same year truck at the junkyard, plugged it in, and had communication with my scanner. But with they key on, the security light still does not flash and won't learn the key to the BCM. The only difference is when I turn the key OFF, the security light flashes.

 

I have code B2960 Security System Data Wrong But Valid in the new/junkyard BCM. Do I need to replace the key and ignition at this point? I just don't understand why the security system will not go into learn mode. It even still cranks and starts for 1 second with the new, unlearned BCM!