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Audi MMI TMC dropout


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Only thing I've heard on new A4's that's possibly related is the occasional dodgy rear screen which carries the aerial. Normally this affect radio reception so I guess it could affect TMC. I am assumming though that the TMC doesn't have it's own aerial. :confused:

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Only thing I've heard on new A4's that's possibly related is the occasional dodgy rear screen which carries the aerial. Normally this affect radio reception so I guess it could affect TMC. I am assumming though that the TMC doesn't have it's own aerial. :confused:

I'll ask him. Its a dodgy Avant 2.0T Quattro, you know how bad they can be!

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TMC is carried over normal transmitters (e.g. Classic FM) as an add-on to the RDS signal.

So if you go into an area where the radio signals that carry TMC are weak it will drop out.

thats what i thought, but he is saying it doesnt come back until he has switched the engine off and on

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If he isn't complaining of any radio reception problems then it's not an antenna problem since the TMC uses the same antennas.

I've noticed that when TMC drops out it can take some time for it to re-appear if he turns off before that happens he could be thinking it's the turning off and back on that's making it re-appear?

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  • 1 month later...

Hi,

Does the car by any chance have 3G MMI with HDD Nav High? If so, this sounds very similar to the ongoing problems with my A6. Symptoms are that TMC stops working and FM stops detecting/retuning radio stations, so on longer journeys radio reception drops out, but this is only noticable if the car moves to an area where the current station is broadcasting on a different frequency. Also TP bulletins disappear.

So far it's had a new radio unit fitted, a new 5F multimedia unit fitted, a new rear window fitted (to replace the aerial), radio boosters installed, and a software update. Five months in and the problem isn't fixed, and the poor tech at my dealer doesn't know what to try next.

I know of another A6 in Nottinghamshire and an A4 in the North East with the same (seemingly incurable) issues - all with 3G MMI and Nav High, so could this be the fourth car to add to the list?

MF.

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Symptoms are that TMC stops working and FM stops detecting/retuning radio stations, so on longer journeys radio reception drops out, but this is only noticable if the car moves to an area where the current station is broadcasting on a different frequency. Also TP bulletins disappear.

Sounds like 3G still has the AF bug that has plagued Audi radios for years...

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You'd expect consistency though wouldn't you?

I'm just back from a 650 mile round trip to Cornwall and hence we went through a lot of different radio areas. The TMC updated regularly and we were paying attention as around M4/M5 is was snarled up.

If it was a coding issue then wouldn't all the cars have it?

Gotta be damn annoying for those who do. :(

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You'd expect consistency though wouldn't you?

Since reception of TMC data relies upon RF propagation, I wouldn't expect consistency - there are too many variables (how many hills, lorries, cars, buildings are in the propagation path, how many reflective objects are near to the path to generate destructive interference due to multipath, atmospheric pressure has a big effect too,...).

RF propagation is a "black art" and the only thing you can be sure of is that you have to be unsure.

You can drive the same route every day for a month and get either 31 different behaviours or 1 common behaviour, and anything from perfect signal to unusable/zero signal.

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Agreed but we're not just talking about signal loss. We're talking about the result when it happens.

You lose the signal, so you lose TMC - as simple as that.

Then the system goes into a "search for a station transmitting TMC data" mode, and if you're driving in an area where stations keep fading in and out then it can take a long time for it to happen to tune to a TMC transmitting station when it's strong enough to decode the TMC data.

So taking a long time to regain TMC data is expected behaviour - even for a well designed system.

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  • 3 weeks later...
Is that true? It's being "assumed" that that's the reason...

Or is it just that it takes a long time to re-find the station, and restarting the car shortens that because it "starts from scratch" again?

It's true.

The problem is more than just TMC though, because the radio stops finding new stations and stronger signals for the current stations, and TP bulletins are not detected. At this point if you select "Update station list", it usually returns with just the current FM station you are listening to and can't see any others at all.

Without switching off and restarting the car (manually rebooting the MMI makes no difference), the only way to get the channels and TMC back is to go to manual tuning and manually scan through the entire FM frequency range finding each station in turn. This temporarily re-enables TMC for a few minutes, but it then drops out again.

Before the last MMI software update, I used to be able to get TMC and stations back simply by switching wavebands to MW then back to FM again. The latest software stopped this from working :(

It's a bit of a puzzler for all concerned!

MF.

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The problem is more than just TMC though, because the radio stops finding new stations and stronger signals for the current stations, and TP bulletins are not detected. At this point if you select "Update station list", it usually returns with just the current FM station you are listening to and can't see any others at all.

Sounds like a software bug to me.

The AF algorithm on the RNS-E seems to have got worse too, since I upgraded to a 2010 RNS-E I'm having to manually change stations to a different one and back to the original much more often.

Seems to me like Audi have gone backwards on the quality of their radio control software on both MMI and RNS-E.

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I'm not sure if I've got this problem or not. I went to Lakeside from M11 Junc7 and didn't get any TMC or Traffic Program. It was a Saturday do I expected less radio station alerts but no TMC is worrying. It was the same on the way back too :confused:

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Hi Scotty,

If this happens again, try using the "Update station list" option a few times. When the problem manifests itself in my car, updating the station list several times gradually reduces the list of FM stations the car can see, until eventually I am left with just the one station I am currently listening to.

Alternatively, if you're on a long journey, listen to a national station whose frequencies vary from area to area, and you should find that a) the radio does not retune as you move from one area to another, and b) the list of local stations does not update at all.

If it transpires you do have the problem, you have my heartfelt sympathy!

MF.

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