No audio after ACM swap

[buzz-dee]

Hi all,

last weekend I disassembled half my interior to drop in a different ACM. I wanted to gain some functionality my original one didn't come with. The new ACM is from a 2016 UK Mustang. Install went fine, the ACM seemed to be working at first (FM stations could be tuned, their names displayed, digital radio the same) however there was no sound whatsoever coming out off any speaker.

I fired up Forscan and found the DSP module throwing an error code:

audio enable short to ground

I had a 500 mile drive to do the next day, so leaving the audio system inop was not an option. I put my old equipment back in and everything was working again.

Now I'm wondering what can be done to get the new ACM to work correctly?

Here are my thoughts:

1) the new ACM hardware is incompatible? Then I'm out of luck on this. Maybe it's just the Audio enable signal coming from the ACM to DSP is located on a different pin?
Is there a difference between MFT and SYNC 3 ACM's (wiring between ACM and DSP

2)AS-Built data needs to be changed? I'm still investigating what the sound system in the donor car was (9 speaker or 12 speaker) and if this would make a difference.


Any advice or suggestions from you are highly appreciated.
I still have hope I can get this done.

Thanks

Sebastian

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[jsn1]

I suppose that you have Shaker audio, and the donor car doesn't.

Could you verify, If this is correct, it can be solved with some programming.

 

[buzz-dee]

I suppose that you have Shaker audio, and the donor car doesn't.

Could you verify, If this is correct, it can be solved with some programming.

That's what I'm hoping too. I've tried to contact the guy I got the unit from. But it's a public holiday in the U.K. today, so I don't expect an answer before the end of tomorrow.
Do you have any hint on what changes in the programming would be necessary and if it all can be done via FORScan?

Thanks for your help

 

[buzz-dee]

So I got the VIN:

1FA6P8CF6H5223104

for some reason I can't access the Ford webpage from here so I'm still not sure which audio equipment that car came with from the factory. Is anyone able to help me out please?

 

[mumbles]

Using that VIN came up with the following...

 

[buzz-dee]

Using that VIN came up with the following...

Big thanks to you Eric!
Well, that means the donor car was using the same setup as my car if I read that correctly?! I don't understand why my setup is not working plug and play. Any ideas on how to proceed from here?

 

[mumbles]

Big thanks to you Eric!
Well, that means the donor car was using the same setup as my car if I read that correctly?! I don't understand why my setup is not working plug and play. Any ideas on how to proceed from here?

If I recall correctly, there were some wiring differences between the 15-16 models and the 17 model. I can't verify what they were since photobucket shit the bed and most of the pics in the wiring sticky are gone :frusty:

The first thing I would suggest is to check the voltage on the audio enable line. Since your wiring from the ACM to the amp is factory, pin #1 on the brown plug going to your amp should go to +6v when the stereo comes on. My guess, given the error message you're seeing and lack of sound is that it never does. Once you verify that's the case, then you could, one at a time, check the rest of the pins on the brown plug and hopefully one of them exhibits the correct behavior. It would be a matter of repining the molex plug which is easier said then done :(

I hate to volunteer other members, but dcjwardog has a 17 model and swapped his 400a ACM for a 401a ACM. He might be able to tell you what pin the audio enable is, assuming it is different.

 

[Falk03]

Using that VIN came up with the following...

Hello Eric
some time ago I found this website where you can see all your options, but sadly I did not notice the page.
Would you be so kind and share the link?

Thank you very much in advance.

 

[buzz-dee]

If I recall correctly, there were some wiring differences between the 15-16 models and the 17 model. I can't verify what they were since photobucket shit the bed and most of the pics in the wiring sticky are gone :frusty:

The first thing I would suggest is to check the voltage on the audio enable line. Since your wiring from the ACM to the amp is factory, pin #1 on the brown plug going to your amp should go to +6v when the stereo comes on. My guess, given the error message you're seeing and lack of sound is that it never does. Once you verify that's the case, then you could, one at a time, check the rest of the pins on the brown plug and hopefully one of them exhibits the correct behavior. It would be a matter of repining the molex plug which is easier said then done :(

I hate to volunteer other members, but dcjwardog has a 17 model and swapped his 400a ACM for a 401a ACM. He might be able to tell you what pin the audio enable is, assuming it is different.

thanks a lot for your advice. I will try to find that +6v wire.

I thought the donor was a 2016 GT, however it was built 08/01/2016 so I assume it's a 2017MY then, isn't it? Makes me think that there might be more wiring differences?!

Maybe someone here has access to the wiring digram of a 2017 GT? I'm especially interested in the wiring ACM to DSP and DSP to speakers.

Thanks again, I really appreciate everyone's help

 

[mumbles]

Hello Eric
some time ago I found this website where you can see all your options, but sadly I did not notice the page.
Would you be so kind and share the link?

Thank you very much in advance.

The site I used is;
http://researchmaniacs.com/VIN-Number-Lookup/WindowSticker/Ford.html

Once you put in the VIN, it initially looks like you are going to have to give them your email address... wait about 10 seconds, and the options sheet will appear.

 

[mumbles]

thanks a lot for your advice. I will try to find that +6v wire.

I thought the donor was a 2016 GT, however it was built 08/01/2016 so I assume it's a 2017MY then, isn't it? Makes me think that there might be more wiring differences?!

Maybe someone here has access to the wiring digram of a 2017 GT? I'm especially interested in the wiring ACM to DSP and DSP to speakers.

Thanks again, I really appreciate everyone's help

Yes, the options sheet showed it as a 2017MY vehicle. If you can find a wiring diagram, please post it here... I haven't been able to find one.

 

[rambunctious]

Sub'd

 

[buzz-dee]

So, today I ripped out my old ACM again and put the new one back in without expecting any change to happen of course.
Then I took some measurements at the DSP connectors. As [MENTION=20499]mumbles[/MENTION] correctly assumed, there is no voltage on the #1 pin at the brown connector going into the DSP. Also, there was no other pin carrying the necessary +6 volts I'm looking for.

Since I didn't know the exact differences regarding the ACM-DSP connections yet, I went the safe route and unplugged all electrical connectors at the DSP for the time. That way I made sure I wouldn't fry my DSP/AMP while doing my research.

Next I purchased a 72h subscription at motorcraft to gain access to all wiring diagrams and connector views and the like. I started by comparing all the connector pins and their associated circuits, wire colors and functions.
The good news is: I think I found the single pin that makes the difference.

On my 2015MY the ACM sends its "audio enable" signal via connector C240A pin #7 to the DSP. On the 2017MY it's exactly the same pin on the same connector :frosty:
Then I compared the other plug coming from the ACM (C240B).
The 2015MY shows pin #18 as not used while in the 2017MY it is used as:

"CTRL MOD. AUDIO # ENABLE 1"

Every other pin out of the ACM or into the DSP is matching for both MY!


Before I tear the dash apart a third time, I would love to know if everything straightens out once I supply the DSP its desired +6 volts on pin#1.
How would you do that?
If I just feed power to that pin to tell the DSP to get moving, I also do feed power towards the ACM pin 7. Do you think it's likely I break or fry any circuits that way?
Also, would you just remove that #7 pin on c240A and relocate it to #18 on c240B hoping all is working thereafter or better put in an additional terminal at C240B #18 and connect it to the original circuit C240A #7? <-- to me, that would be the same as if I just put the power wire directly to the DSP.

Thanks for staying with me, I hope my text is not all too confusing.

 

[solodogg]

Might I take this back to the original and inquire about what you were trying to gain with the new ACM that your existing couldn’t provide? You might have been better off with an OBDLink MX and FORScan...

 

[buzz-dee]

Might I take this back to the original and inquire about what you were trying to gain with the new ACM that your existing couldn’t provide? You might have been better off with an OBDLink MX and FORScan...

Sure, NP!
I decided to buy the US spec model for several optical (hood vents, red tail lights, illuminated tribars) and technical reasons (3.73 gears, BLIS, adaptive cruise, cross traffic alert, collision warning), all of which are not even an option that can be chosen when ordering the EU spec model here in Germany.

The downside is that the entertainment system is US spec as well. On the FM side you can only tune odd frequencies (e.g. 92.3 or 91.5) where a lot of stations over here broadcast on evens (104.8 or 92.2) <-- that problem can be solved by changing some bytes with FORScan, which I already did. Now my radio can tune all the frequencies however is not able to display the associated names anymore (that's a known problem, you can only have one OR the other).

I've tried each an every trick to overcome that, even overwrote the whole ACM / APIM configuration with the one from an EU spec car. No dice.
I strongly believe that it can be done, but not with forscan. Maybe one would have to write a different (EU) firmware to the ACM but that's beyond what forscan or I'm capable of.

The second caveat is Sirius XM and HD radio. Both are of no use to me. They simply don't work in Europe however I like the idea of high quality digital audio broadcast. We do have DAB+ over here (being a terrestrial broadcast instead of satellite) and all the EU Mustangs can receive it but the US ACM does not have the required hardware. So there's nothing forscan can do about it.
When you try to activate the feature with forscan (which I did) the ACM starts throwing DTC's.

There is one guy over here who is offering to do the required hardware and software changes but he's asking close to 2200$ for it. Since he's the only one and did all the research and testing himself it's totally on him to make the price. For me it's far too steep.
So, that's how I ended up trying it myself. I believe I'm really close and with all of the knowledge floating around in here it is within reach.

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