I have an 2006 Trailblazer SS LS2. It has an E40 PCM. Always ran great. I killed the battery the other day and slapped a battery charger on it. Well the charger was way too many volts and after the charge the PCM started throwing P0601: an Internal Control Module Memory Checksum Error code. The motor would die at idle. I would shut it off and after two minutes it would start again. 20 miles or so later it would do it again.
Luckily I just got HP Tuners and saved my tune file while everything was still working good. I figured what have I got to loose so I did a FULL rewrite of the PCM and it totally fixed the problem. Maybe other already know this but after searching the internet for 2 weeks I found nothing but P0601 means new PCM. Not so in my case.