I'm going to bring home my laptop and MDI from work, programming it back to stock, and reloading the tune. If that doesn't work I'll warranty out a new ECM!

 

PCM's do have a "flash life", they can only be flashed so many times. It's a huge number though, something like 10,000 or 100,000 though, good luck hitting those numbers.

 

Starts and dies?? Is the security light flashing? Might need to just relink or disable the VATS.

 

Try an entire write with a known good file for your truck. If it was corrupted or didn't flash properly it should work and the truck should start. If you flash it back and it still doesn't start you may have an electrical issue.

Are you sure you're not suffering from the same electrical issue that all the other GMT 900 trucks have with the loose connection under the fuse block in the engine bay???

This seems to be a very common issue when there is a random no start condition present on one of these trucks.

I would at least take a peek before you replace anything. It could just be a coincidence.

 

Fast brick what connections are you talking about? My buddies NNBS has random start issues.

 

Big fuse block that snaps into a cradle on the driver side by the fender

 

The underhood fuse box. The connections that go into the bottom of the box can be loose or have broken pins. The large 175 amp maxi fuse can have issues too. And last but not least check the battery cables and connections, if there is corrosion replace them.

 

Ran into a lot of the junction block connections at work. Seems to be really common and most of the time when it does that the vehicle won't crank.

Mine is definitely tune or ECM related. The only time it ever does this is after I've put a new tune in..... Originally it started when I switched to speed density and my tuner had the MAF table zeroed out. I put the stock table in there and it fixed it for awhile but now doing it again. Makes it a total pain in the *** to fight with it! No security light at all. I can watch the dtc's and as soon as I can get a MAF code to set it will be fine and run.

 

Put it back to stock with GM hardware/software and put the tune back in. Started, set the P0102, and ran......Not sure what the deal is but it works fine. We'll see with the next tune if it stays that way!