I think I may have mentioned this issue briefly a while back on the Focus forum but thought I'd better come here to look for expert advice. It concerns the audio system on my son's 2013 S-Max Titanium 2.0TDCi. After returning from a foreign holiday he had to get the car jump-started after finding the battery too low to start it. This is his summary of the history of the problem:

"The issue started in 2023 after a breakdown service tried to jump start the car with a battery pack that was too small and not powerful enough. It sent all of the dashboard systems into a frenzy and relays clicking etc.

After that the audio started randomly cutting out emitting a very loud inteference fuzz sound/white noise sound. The only way to stop the noise was to turn the engine off and lock and unlock the car. When the engine was restarted the car system had been reset and the audio worked again.

The issue persisted, becoming less random and more frequent, until last October the radio went bang and all audio was permanently stopped. The radio was on but no sound came out. The audio affects all systems including radio, cd, phone and parking sensors.

The head unit has been repaired 4 times and refitted and each time it works fine for 24 - 48 hrs and then immediately goes pop again."

I understand from him that it actually does go "pop" and then emits the mush noise at full volume which can't be turned down with the volume control. As far as I know he had the work done by a Ford garage and has not received any feedback about what was done. I've suggested to him that it might be worth reinstalling the asbuilt file to the ACM if he could establish that's not already been tried. I've been a bit nervous about doing that as I've never attempted it before but maybe now we've little to lose.

The jump-start caused all manner of other problems as well, with the central locking and windows. I ran FORScan and predictably lots of DTCs appeared. After saving the log I cleared them and then re-read them to see whether any were persistent and we managed to get the locking and windows working again but the audio problems persisted. I have copies of the two logs I took in 2023, when the problem first arose, and two more from 2024 These last two may be pertinent as they show a DTC for the IPC and one of them also has one for the ACM. I've attached a photo of the audio panel to aid identification. I was hoping to attach a zip file with the logs but the file type isn't permitted. If anyone wants to look at any of them I can attach them individually as .txts.

I'd be grateful to receive any suggestions.

Firstly I'd recommend disconnecting the negative battery lead for at least 20 minutes.

Then reconnect the battery and WAIT for at least 5 minutes. This will reboot all modules and will enable them to boot in the correct sequence.

Check that the battery terminal voltage is at least 12.50V and if all is well, then turn on the ignition and allow the radio to power back up (input code). Then start engine, and see if normal service has returned.

Easy thing to try I suppose. Will the window auto-close need to be relearnt?

To be honest my gut feeling is that though this may clear the fault it probably won't result in a permanent fix. I had a feeling the battery had been changed after the jump-start and needed to check with my son which is why I've delayed replying. Turns out it hasn't but since the car's been into the Ford garage four times with this fault do you not think it would be something they'd have tried?

7 minutes ago, mjt said:

Ford garage four times with this fault do you not think it would be something they'd have tried?

Most probably not 🙁

I thought you'd say that .

Hi @unofix we may be trying out your recommendation later this week. You didn't answer my query about needing to re-learn the auto-close. Will we have to do that and if so what's the procedure?

The garage have washed their hands of it so, short of taking it somewhere else, it looks like we're on our own.

Resetting auto-close is as simple as closing the window, then holding the button in the closed position for 2 seconds.  If it's auto open & close then you need to do the same for open as well.  And if all 4 are auto then you need to do each window individually.  Looks like a faff written down but it only takes a few seconds in practice.

On 7/3/2025 at 10:43 AM, mjt said:

Will the window auto-close need to be relearnt?

Yes each window will need to be re-taught their position, assuming that you have both 'one touch' open and 'one touch' close on each of the door windows.

Simply press and hold down the open window switch and keep it held down even when the window is fully open. Keep it held for about 10 seconds and then release the switch.

Next pull the switch up to fully close the window, keep the switch held up even when the window has fully closed. Keep it held for about 10 seconds and then release the switch.

Repeat for each window. 👍

Well, it didn't come to pass. Haven't heard anything from the lad so don't know when he might want to try it. The idea is to do it at his workplace during his lunch break so the car will have stood for 3 to 4 hours before we test the battery voltage. I'll see him over the weekend so might find out more then.

I learned a bit more this week. It turns out it isn't a Ford garage my son's been going to so I'd say it's unlikely they'll have tried the reboot you suggested @unofix and extremely unlikely they'll have tried a re-install of the as-built data. They have said the radio keeps "blowing up" the amp. What they mean by that is unclear but to me this appears to be a new fault. Originally the radio gave a loud pop followed by white noise at maximum volume that couldn't be turned down. Now it seems once the fault occurs there is no sound at all from radio, parking sensors or anything else, as described in my post on July 1st.

It's looking as though I might get a chance to look at it around the end of August. My son has very little free time and his car is in constant use so once I'm sure of a date I'll get hold of a free temporary FORScan licence so I can try the as-built re-install if the battery re-boot doesn't work.

The saga continues . . . . . . . .

At the moment I have absolutely zero knowledge of the audio system fitted to this model of S-Max. Is there any information and/or schematics that I could look at, similar to that posted by Preee on the Focus forum?

 

Well, I didn't get a chance to do any more with it until yesterday when I took the opportunity to check for any new codes whilst investigating a problem with their C-Max. These, shown below, were the only ones found. Note that they're all the same as I reported in a thread on the Focus forum last year. Nothing's changed. Currently there's no audio of any kind (radio, parking sensors etc.). Since the codes show the IPC has lost communication with the radio and the ACM has lost comms with the BCM am I right in thinking the comms pass from the ACM to the BCM via the IPC? My son has been considering trying to source a used ACM but I'm wondering whether the fault lies within the IPC.

When I looked at the Configuration & Programming panel in FORScan it only showed an Asbuilt for the IPC, nothing for the ACM. I note that @DaveT70 recommended reloading the Asbuilt for the IPC in his reply on the Focus forum on 2nd May last year (yes this saga has been dragging on that long!!). As I'd said in that thread I'm quite nervous about playing around with reloading software, especially on something as vital as the IPC, as I've not used FORScan much.

As always, any observations on the above will be gratefully received.

Codes read 29/12/25:

===ACM DTC U0140:00-28===
Code: U0140 - Lost Communication With Body Control Module

Status:
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Audio Control Module

===END ACM DTC U0140:00-28===

===IPC DTC B1A84:51-2B===
Code: B1A84 - Car Configuration Data

Additional Fault Symptom:
 - Not Programmed

Status:
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Instrument Panel Control Module

===END IPC DTC B1A84:51-2B===

===IPC DTC U0184:00-2A===
Code: U0184 - Lost Communication With Radio

Status:
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Instrument Panel Control Module

===END IPC DTC U0184:00-2A===

 

My money is on head unit is dead, no comms

Check the comms wiring going to the head unit first, but I think it's dead

You may well be right Dave but before throwing any more money at it - the lad has already spent a considerable amount for the garage investigations - I think it would be worth trying reloading the Asbuilt.

I must confess I'm not wholly conversant with the terminology. Is the head unit with all the radio controls what is being referred to as the ACM?

Would the fact it's lost everything that uses the audio system, like parking sensors, imply that it's the power stage that's blown (which is what the garage is saying) rather than the head unit? Is the power stage a separate assembly?

According to what I've been told the audio system has been sent away for diagnosis and repair on more than one occasion. I have no way of knowing whether that included both the head unit and power stage if they're separate modules.

With the lad's current lifestyle I can't see me having access to the car for long enough to carry out any detailed checks besides which we don't have a Haynes for the car so no information on how to disassemble anything and no circuit schematics.

Edit: Just ordered Haynes. At least I'll be able to get an idea of what I'm dealing with before I see him again. Then I can give it to him as a birthday present as it's this month .

Yes, head unit is ACM

Having received the Haynes it's proven to be of very limited use (maybe predictably). There are some quite detailed circuit schematics but they only show wire colours. None of the signals are annotated and so far I've not been able to identify any CanBus signals so I can't trace which modules the buses go through. Quite disappointing.

1 hour ago, mjt said:

There are some quite detailed circuit schematics but they only show wire colours.

Here is the link to the full 2013 Ford S-Max wiring schematics.

It's on my personal Google drive at the moment 👍

https://drive.google.com/file/d/1a0RfFRCXPd2_12_3zGp-ouGab2t-WOxW/view?usp=drive_link

That's brilliant. Many thanks for that Uno.