p1518 code after 4896 to 0411 pcm swap

[spinne1]

I have a 1999 GMC Sierra 1500 4wd with 4L60E. It stopped shifting so I pulled pan and changed filter, fluid, and all solenoids/wiring harness (all acdelco). It still would not shift so I did troubleshooting and found that the computer was bad. (It would not ground the Shift Solenoid B--code p0758. Both the 12V wire and the solenoid B wire checked out and I also could get it to click and it had about 21 ohms though the new solenoid.) I did a bunch of research to find out which computer would be compatible then went to a few junk yards. I only found one computer, a 0411 PCM from a 2001 Suburban. I installed it then did the relearn procedure, which went fine. The car started and ran great for a few seconds then barely ran at all. It pulled a p1518 code. It is in reduced engine power mode. I pulled the pcm pinouts for both vehicles and tried to see where differences would be and if it could be rectified. I found differences but no direct connection (each vehicle had pins for things the other vehicle did not have). I have read of others who swapped with no troubles, so I ask, do I likely have a bad 0411 PCM? If it is good, I'd like to just sell it on eBay for cheap as I have since gone on eBay to get the correct pcm for my truck with the vin flashed (4896 pcm.) But I'm curious how to fix a code when that code doesn't seem to exist on my 1999 vehicle, nor does the TAC that is referenced in the code. Ideas?