When I read my PCM I got a "checksum error" on engine operation and I thought it might have had something to do with the modified tune that was in the truck at the time but when I finally got it to take a reflash and re read it it still showed a checksum error on engine operation but the tune was changed?? Any ideas?? I dont even know what a "checksum is"
This is on a 2006 LBZ 4x4 allison