AU2 & AU3 I6 ECU/PCM Catch Codes and LPG?

[asimplelife]

I haven't been able to find my own answers to these ones.
So am hoping someone with more knowledge can help me out please.

I wonder if it was entirely necessary to have so many PCM/ECU catch codes :(
I can see why VCT, XR Auto Adaptive Shift, Dedicated LPG, Dual Fuel LPG, Police Option 20, Fairmonts and Fairlanes would be different.

1. Apart from that, are all PCM/ECU's the same across sedans, wagons and utes? With the BEM handling any differences?

2. And why do some PCM/ECU's have the codes changed in texta?
For instance a 12MB was changed to 12MC.
My theory is this is likely when a Ford dealership has re-flashed them for some reason? (when they remembered the texta

3. Finally, to my real question, I have a PCM with catch code 12MB and handwritten in texta (of course) is "AUII Ded Gas Man".
According to the PCM "lists" this should be an; AU2 4.0L Manual, File name NGIC6M4, PCM Part Number 1R23-MB, Module Id ETV-735.
There is no mention of Gas or LPG for a 12MB.
For LPG Dual Tickford it should start with 12Z.
And for LPG Dedicated it should start with 12L.

In my manual conversion into an after market dual fuel S3 Op20 auto sedan, using FORScan PATS I successfully connected this 12MB PCM. The engine turns over. However it would not start. Which I assume tells me this PCM is somehow dedicated LPG. So it must have been dealer flashed to LPG at some time? It's not got a J3 chip.

Anyway, I can buy another 12MB PCM for $100, but it would be a shame to waste more money to get the same result.

[asimplelife]

Well, I am digging myself into a bigger financial hole here
But perhaps I have made some progress?

To recap, AU3 opt20 auto sedan after market LPG with auto PCM 12ED.
Have done a manual conversion. Tried the resistor trick. But was still getting high idle.
Had a spare manual PCM 12MB (I hoped).
Hand written on it was "AUII ded gas man".
But I could find no record on any AU ECU/PCM list that indicated this was an LPG PCM.
Although it is supposed to be a manual PCM.
Was able to pair to my BEM with Forscan PATS.
Car was turning over but would not start.
To me this meant it could actually be an LPG PCM?
So I returned to the 12ED PCM.

Bought another hopefully manual PCM 12MC.
It had no mention of LPG just "Ford AU XR6 manual 2001".
The AU ECU/PCM lists also don't mention LPG.
However exactly the same thing has happened. Turning over but would not start.
Although this time, while it was not starting, I noticed "LPG" flashing on the instrument cluster (this could have been happening with the previous 12MB).
I note that "LPG" did not ever previously appear on the instrument cluster with 12ED.
I am advised that with after market LPG conversions, nothing should be touched on the original PCM that would affect this?

I then went back to the 12ED which still worked.
Then tried pairing what should be my VCT manual PCM/ECU 22AA.
AND IT WORKS! (I am swapping in a VCT engine later on).
So my idle problem is resolved (although I should now remove those resistors).

It seems I may now have 2 LPG PCM's I cannot use though
I'll put them on the pile.