PCM corrupted / damaged out of the blue?

[Boost]

My vehicle (LS1B PCM) is licensed and tuned, new battery in good condition. I went to routinely read/write it for like the 100th time lol and it says "FAILED TO UNLOCK". I am not sure what gives, tries most of the common sense basic things and still.
When I go to read it acts as it has a custom lock by another tuner (impossible) and when I go to cal. or full flashed it says not licensed (impossible).
All of this happened on it's own, and if it helps at all I recently ran my 4 year old battery dead by having the key on / engine off to test and replace a blown instrument cluster fuse. I installed a brand new good and proper battery and the car runs great except... for some possibly unrelated reason it now idles slightly and intermittently high. Meaning the "dashpot" (?) it likes to sit at 1100 RPM for no reason until it settles.
What happened to my PCM communication with tuning device and what to do please?
Greatly appreciate in advance you time/attention/clues/help/suggestions!
Don't want to buy another module until I am sure and I understand the cause. Money is tight and an accurate diagnosis is essential. But I am only halfway done tuning this piggy
Vehicle is 2001 Z28 manual / stock LS1 - bolt ons if it helps

[Y2kHawk005]

Check for corrosion. I recently went through this..

[Boost]

Check for corrosion. I recently went through this..

Will disconnect and clean/service (properly) both connectors asap! Will update results. Hoping for best, wish me luck and continue adding insights please

[Boost]

Update:

Disconnected the negative battery terminal
Disconnected the positive battery terminal
Waited 10 minutes
Disconnected both PCM connectors
No sign of corrosion or other obvious problems
Sprayed liberally with electrical contact cleaning spray
Brushed lightly with soft toothbrush
Dried and coated liberally with dielectric grease
Reconnected everything carefully and properly

Car starts and runs great, check engine light comes on with all the other warning lights when it should - KOEO

Same problem - can't tune or read

Is my PCM possibly hopeless or should I check "No Communication With DLC" type diag. (does anyone have flowchart / schematic)

The thing is it identifies itself, says all connections are good and tells me the vin. Just the UNLOCK fails.

It is (falsely) behaving like a locked and unlicensed module

pwease halp

[cobaltssoverbooster]

have you attempted to read the ecu in low speed communication mode? its should be a read option inside the read menu prior to activating read.
not really a flow chart.. typical interference with reads are erroneous can messages and voltage fluctuations. pull fuses to aftermarket radios if any, remove power from aftermarket remote starts, and keep voltage constant with some sort of charging or trickle unit during read.
if these dont work then a bench flashing harness can be made with spare parts from a junk yard. if the flashing takes properly on a test harness then you have an issue with something in the chassis


try to read the ecu. when it pops an error save an info log so you can send it to hpt tech for guidance

[Boost]

Thank you! and sorry for the late reply. Yes I tried that, the PCM simply got corrupted somehow. I did have some electrical issues in the weeks prior. Installed a new one and good to go now. On to the next problem... lol. Thanks again everyone

[Asylumwarp]

Too bad I wasn't on a week ago.. If you had a tune from the pcm prior to data corruption, I most likely could have reinstalled it on your pcm. I can unbrick them. Seems you used 2 more credits on new pcm then just did a write entire to the old file for the vin swap?

[Boost]

Thanks and no I got a PCM from Ebay for $99 with the same VIN the tune files were saved on my laptop

[TheMechanic]

For about 10 or more years now GM wants dielectric grease on every single connection. They have had issues with water intrusion, corrosion and fretting. I have begun to use it on all electrical connections. Good insurance.

[blindsquirrel]

spam spam spam spam baked beans spam spam and spam

[schpenxel]

Keep reporting spam if seen. I usually delete them pretty quick once reported.

[2xLS1]

Never noticed this place has moderators.

[schpenxel]

I haven’t posted much the last year or two but I try to take care of anything that is reported.