Flash new ECM question

I am having an issue with a 06 TBSS and leaning towards it being a bad ECM. I know it sounds unlikely but have ruled out most other things.

First of all the truck has a 408 in it. I had it dyno tuned and the tuner used EFI-live to do so.

Shortly after that I started getting a P0353 code (primary circuit coil 3) and when the TCC locks up it chugs. I am not positive they are related but I am not going to troubleshoot the chug until I get rid of code. When I say shortly after I mean it ran fine for a couple months/1000 miles.

I dont think its tune/EFI related unless its something to do with custom OS. I flashed back my HPT tune and the issue is still there.

I swapped coils to another cylinder and the problem stays with #3. I bought a new coil connector and soldered the 12 volt, ground and reference wire to the #1 coil since they are all common wires. I ran a dedicated test wire back to the ECM for the IC "trigger wire". Still sets the same code.

So main question unless someone has something add to my troubleshooting is about swapping ECMs. Can I do everything with EFI live? I realize I need to do a case relearn when I do this and a security learn if the ECM is used. But was not sure if EFI would take care of entire OS, etc?

I hate to go this route as there is not only the cost of ECM but of course I am burning credits on my EFIlive and HPT (if I decided to keep and use it).

This GM part number covers a lot of vehicles and some can be bought cheaper than others so did not know if I could buy a same PN out of a Buick without doing additional work.

Hey Rich, if you want to pick up a new/used ECM, you'll need to make sure the ECM DBW controller is compatible with the TBSS. I'm pretty sure the E40 falls under the typical Gen IV ECM process where you cant buy any E40 and slap it in, it needs to have the proper base platform or the ECM can corrupt itself when flashed via GM SPS. If you use a brand new ECM, this wouldn't be an issue but for a used one, might pose a problem.

You'll need to write to it via GM SPS/Tech II to get it squared away the first time, then re-license it with EFILive (and HPTuners if needed).

Thanks Erik

I kinda expected as much. I have dealer friends than can help although I think the Tech II for them is a thing of the past. Everything is done with their notebooks now!

There are companies that sell them ready to go. I can handle the flash, case and security learn but did not want to have issues with base OS. This is kind of a long shot anyway even though I have eliminated everything else.

Rich

Yep, pretty sure it's all via MDI now. A new ECM is pricey, perhaps buy a used one from a reputable source or an eBay unit from a TBSS (or 5.3L TB)?

Erik,

They are about the same price. Amazon GM new is about $190 and Ebay flashed with VIN is same. I know they can be bought used for under $75 as I see them on TBSS site on occasion.

I am not even sure this is the issue. If I find one I might see if I can route it through Matt (LT1Z) or Alvin and get them to flash one of my HPT tunes using commercial licensing. Then if that fixes it I will feel better about buying credits