[Cobrajet67]

Thanks a lot for the thorough response. Here are answers to the questions you have.
1) I did install it myself. It came with a Kenne Bell proprietary flash tuner supplied by them with the kit. The last step on the install is to flash the pcm with their tune. Kenne Bell had specific questions on the pcm I had when I ordered the kit and needed my pcm code (DHW0) to write a specific tune I’m assuming. It initially flashed just fine and did run just fine for a few weeks, till this happened. No issues at all.

2) I did try and reflash it using the same Kenne Bell supplied dash tuner. It was able to reflash the tune successfully according to the readout on the tuner through the whole process. Nothing changed though after the reflash. Same issue

3) I will try and contact Kenne Bell as well to see if they can help.

I will also give your OBD2 test a try, I have a multimeter and it seems pretty straightforward.

I found a used PCM online with my same part number (dr3a-12a650-aha) and bought it at a fair price. I plan on keeping the car for a very long time so worse case scenario is I have a spare. I am not just going to pop it in though. I’m afraid if there is some sort of a short it might fry the replacement pcm.

Once I try the OBD2 plug test I’ll report back. Appreciate the help, it’s been challenging to try and figure out what this is.

The PCM would have to be flashed with your original Ford program and then reflashed with the custom tune. As I understand it, without it being initialized with the instrument cluster it would basically be a brick and not start the car.

CanBum -

You are absolutely on the right track and doing all the right things! You scored good with an exact replacement PCM. Well done!

Yes, you should check all your fuses. I discovered this link below on this forum sometime ago and saved it for my reference. It is a complete wiring diagram for a 2011-2014 S197 Mustang. It has help me on many occasions and I wanted to share it with you in case you don't have it.
Ford Workshop Service & Repair Manuals - fordrepair.info - 2011 Mustang 2011 Mustang 009 - wiring harness overview (iihs.net)

For example, you could use this bit shown below to check all your powers and grounds to the PCM. Somewhat surprisingly, there are more than one! Mind you, this is tedious & delicate & difficult and time-consuming trouble shooting But you can backprobe (again with automotive T-pins) the big connectors at the PCM
These pins should allhave 12V power - note some are constant power and some are KOER

• Pin 62 white-red wire
• Pin 68 green-blue wire
• Pin 67 green-blue wire also
• Pin 42 yellow wire

Likewise, pins 69, 70 & 50 - each Black-Blue - go to ground and are easy to test once you can get your hands on them!

Hint: A best practice of mine was to print these in color at my work office after / before regular hours on 11" x 17" ledger size paper. We were allowed "incidental use" of all the IT equipment for stuff like this. Makes the task a lot easier and it good to have to mark-up the ones you've already tested.


View attachment 794169


This would be my next step. If everything checks out, it is another nail in the proverbial coffin before you decide to put your PCM in the graveyard. You can save yourself several hundred bucks in labor and a tow by doing this too!

You could also use the CanBus diagrams in Section 14 to your advantage. This is where things get real tricky, real fast and now you're searching and finding all those modules that your PCM can't "talk" to on the network. I have seen some instances where one bad module, e.g. the TCM, because of the way everything is connected together, can seemingly corrupt a lot of other things. This is kind of like parasitic draw testing. You can just start unplugging modules - should you wish - one by one and see if one unplugged modules clears all the codes (except for itself).

This thread shows the pin locations at the PCM!
PCM Technical help needed - Please Read | Ford Mustang Forum (allfordmustangs.com)

HTH and keep up the good work.
Andy

PS: Please post back when you know more. It helps everyone learn.

All good advice but there is no TCM in the Mustang at least up to the 2014 as the transmission control is integrated with the PCM and always had been. I've also never heard of any TCM being in the 10R80 auto equipped models from 2018-23. It's possible that the last GT500s with the DCT trans may have had a separate TCM though, idk. Other Ford models sometimes had a separate TCM like in the notorious 2012-18 Focus with the DCT trans.

I also recommend checking basic system power and ground connections especially when hit with a bunch of unrelated, unusual, and unlikely codes. You have communication codes with the PCM, ABS, FCIM, and key transponder(PATS). A poor ground connection at the engine block or various body points can cause strange electrical gremlins as can a bad power connection somewhere. The PCM relay is something to test and maybe swap if there's another of the same part # in the fuse box. Also, look at any of your relevant fuses to make sure that none have blown. There are several for the PCM for instance.