Fixing the BA PCM/ECU 'wont start cold' issue

[RainingPistons]

Ah yes speedruino I was looking into that but yea getting all the essential things for the falcon seems like a freaking nightmare possibly that's why no ones yet to make a budget ecu which you'd think after maybe 10 years someone would have, is you're a barra or a v8? And yea that's true 4.5k just to drive the car around normally and not need all the extras is crazy for the price hence why I've still got my xr8 sitting here after 2 years as I've never found anything worth spending that money on especially to just drive it around town even though it's a v8 to be fair I just can't warrant the cost of the haltec or the ecu repairs constantly for what the cars worth and it only has 205 thousand ks on it 

[ValleyKing]

I have the Barra

[RainingPistons]

Ah yep I'm sure with the barra surely someone has or is in works of somthing surely since I know the xr8 is abit more complex with those extra strategies ect that they need but the barra I really don't know why someone hasn't yet like it really shouldn't be that difficult for Falcons since people have done it for other ford models in the US and UK could possibly message some sort of Chinese workshop or programmer etc since they make heaps of stuff like kess v2 knock off's and basically every automotive tech things that's popular so I'm sure someone over there would easily be able to create somthing like the haltec and have it at a few hundred im sure of it, just maybe they don't know we need this might see if there's any sort of people who I can find that would be willing to make somthing similar ill do some research and see if I can possibly find anything useful that could possibly actually get this idea to a real product 

[xr6tForMe]

On 16/06/2025 at 2:05 PM, ValleyKing said:

The plan is to get a replacement, clone the original, and put that in before opening up the old one.

Whereabouts are you located?

If you are in Sydney, I would be interested in helping out. 

I might have access to a hot air soldering station if that would help.

[ValleyKing]

Progress update:

1. Received the replacement ECU. Opened it up from underneath for practice and to have a look at its condition. Its a slow and fiddly process cutting away the silicone seal and gradually levering the bottom panel open, but overall not difficult. The underside cover is thin aluminium and will bend when you take it off. Overall its a safe process as there is a good amount of space between the seal and the board. The unfortunate thing is the entire board was sealed with clear silicone and this has it stuck to the inside of the case even when the screws and bolts holding the board are undone. That is going to make checking the board a lot more difficult that it needed to be and may necessitate cutting open to ecu along the sides to access the top side of the board.

 

2. Resealed the replacement ECU and installed it. After some fiddling with Forscan I got it programmed to my keys and recalibrated the control panel (ACM) to get rid of the security code error.

 

3. Now, the engine starts fine in the cold (double confirming ECU was the problem) BUT its not connecting to the speedometer, meaning it wont change gears

 

So some progress, but still a bit of work to do. Not going to open up the old ECU until I have the new one fully functioning

[RainingPistons]

Nice and interesting is the ecu you used the Same trans same gear ratio?

[ValleyKing]

I seem to have hit a brick wall with Forscan. The replacement ECU does not have a VIN and there seems to be no way to write a VIN to the PCM.

 

From what I have read this could be the cause of the lack of communication with the speedo/trans.

 

Can anyone recommend other software to do this?

[ValleyKing]

More specific information from some further research. The "Speed Signal Output Control" setting in the new unit is "ABS only" and in the original ECU it is "Traction Control System". For this unit FORscan says it can't write it directly (which is ridiculous given that it is able to rewrite data to that section during a full flash).

 

The motorcraft website from which they download asbuilt data files (.ab) returns a blank file for the BA VIN's I was able to try. Without a copy of the .ab files, or a spreadsheet with the data locations/vales, or a proper piece of software that is willing to write that data directly, this is a dead end.

 

If anyone has a .ab file for the BA, please let me know. Alternatively if anyone knows an autoelectrician who can flash that specific unit let me know because all the ones I have contacted so far can't do it

[RainingPistons]

What is the New ECU Stickers Numbers like the ABU- and all that stuff and the ABS Module numbers also look in the drivers door panel if there's a tear tag it'll have abs codes and everything and software Cal etc  

[ValleyKing]

Its the same trans and engine but it is coded to use ABS to calculate vehicle speed, whereas my car uses the TCS, so it will run the engine but wont detect speed (hence wont ever change out of 1st gear)

The data for that is in the VID block which apparently on this model can't be written to without flashing the entire unit (according to forscan). Full vehicle .ab file is not available to do a flash. Been searching far and wide but no-one seems to have it or be willing to share it (and no its not available from motorcraft) . Kinda frustrating to know exactly what the issue is but being unable to fix it because it was deliberately or idiotically designed to be unfixable. A single byte of data needs changing. I know what needs to be done but lack the software to do it

Again, if anyone has a full spreadsheet of data locations with a piece of software that will write them directly, or a complete .ab file for the BA PCM unit, those the only things that will get the job done.

Otherwise my best bet is to find an exactly matching unit and hope it doesn't have same issue