Bricked L31 controller X 2

[Oldude]

Been playing with the latest v8 and scan/tune v3 for a few weeks now. I started with my stock 1999 Yukon 5.7l vortex that needed the engine rebuilt. I played with tire sizes and such.

I got around to changing the engine about 2 weeks ago, went with a mild cam trick flow heads short tube headers, cat delete y pipe n stock mufflers. Stock bore engine.

I'm up to my 3rd iteration tune, have only messed with shift points and DTC stuff.

The rub came about a week ago, I flashed a tune into the stock l31 ecm and got a no start. Only edited shift points on a proven tune. Then the ecm bricked. I drove a spare to work that day. Got back in to realize it wasn't just a bad load but the ecm wouldn't take any cal upload.

Swapped ecm and used my last license on the same vehicle and downloaded that tune. Drove it for about a week and changed shift points and re flashed it. Came up with vehicle security switched back on in my tune so it wouldn't run. I edited the tune, reflashed it only to have it not taken a flash... Again. Returns a $0281 error. Both ECMs now won't auto detect and show nothing but 0's where there used to be data.

The Yukon is bone stock electrical wise even has the stock radio. I have downloaded tunes with and without the radio fuse being plugged in, mostly with the fuse pulled.

So now I'm trying to clear the security on the third ecm so I can drive it again. I'm afraid to attempt to touch this one with efilive hardware or software. Not sure what my next step is...

Any help is very welcome.

[Oldude]

No ideas from the community?

I expected at least some "you dumb a$$, you shoulda done x y or z's"

I don't know where to turn from here, my Yukon is stuck in the shop with no start.

I'm going to buy a used ecm or 2 but really don't know what I did to cause this, twice.

Did I get faulty hdw or did I just dork it up?

Really, any input will be appreciated.

[ChipsByAl]

Make sure you can read the new PCM a couple of times successfully first. Maybe program that new file back in to be sure the file did not get corrupted some kind of way.
Al

[Oldude]

Thanks al,

I have some new/used ecm's being shipped to me. The trouble is I've consumed both of my vin licenses on the two bricked ecm's that now show zeros where the vin and os versions used to be. So two licenses on one vehicle and neither is valid. This is getting expensive!

My fear is if I purchase another vin license for one of the new (to me) ecm's then I get 3 or 4 cal flashes then bricked another one.

Hopefully you can see my dilemma. If I knew what I did wrong and could assure it didn't happen again it would be easier to continue with a new ecm/license...

[nonnieselman]

This is when things fun....
Ive bricked a few L31 PCMs. Ended up just swapping it for a LS1B pcm and rewired the harness to LS connectors and never had any more problems.

[Oldude]

I hear you nonnieselman,

I knew this wasn't going to be an entry level endeavor when I started.

efilive has me fixed. I was able to unbrick one of the two and I'm driving again. It turns out I had old firmware.

I started to rewire for an 0411 until I found the pinouts spreadsheet impossible (for me) to get a hold of and I really wouldn't gain anything for my application.

I'm currently trying to build a bench harness. I haven't found any two pinouts to be the same and none of them have complete circuits depicted.

I think I only need the black connector but again, not sure and I have enough smoked hardware.

[nonnieselman]

I hear you nonnieselman,

I knew this wasn't going to be an entry level endeavor when I started.

efilive has me fixed. I was able to unbrick one of the two and I'm driving again. It turns out I had old firmware.

I started to rewire for an 0411 until I found the pinouts spreadsheet impossible (for me) to get a hold of and I really wouldn't gain anything for my application.

I'm currently trying to build a bench harness. I haven't found any two pinouts to be the same and none of them have complete circuits depicted.

I think I only need the black connector but again, not sure and I have enough smoked hardware.

Want me to send you the Lextech spreadsheet he made for this swap?

[Oldude]

Sure.

I have a couple of these 99 vehicles and would like to try the 0411 for myself. I also have all the 0411 plugs and 2 known good ecm's

[ChipsByAl]

I would second the upgrade to the 411 PCM. The wiring swap is not tough and the tuning capacity is considerable. I did my first upgrade to the black box PCM on a 1997 truck over twenty years ago.
Al

[Oldude]

I have so many L31's now, I may pull one apart and make an adapter interface. L31 sockets on one end and 0411 plugs on the other.

[Oldude]

@nonnieselman

So new to this forum, I can't seem to find the private message button

I have an L31 apart, I'm about to remove the sockets and actually build the L31 to 0411 interface cable.