[madgerald]

Hi there

I thought I would post this question as I couldn't find a thread with my specific problem but please point me in the right direction if this has been asked before....

I have a 2006 335i with the Professional head unit fitted. For a while the sound has been cutting out for 4 - 5 seconds at a time (typically it does this for 20 mins) on a regular basis then sorts itself out for 20 mins then cuts out again etc.. It does this on all settings (tuner/aux/CD).

I bought a used head unit on ebay (identical apart from no bluetooth) and fitted that instead - result was the problem persisted and I cant believe that both units have exactly the same fault. I therefore assume it's the amp (if this system has one ) or a wiring fault.

So what could the problem be and how do I go about getting it fixed? The local specialist wants £600 for a new amp (without seeing it) but is there a cheaper option?

Thanks if you can help.

Bill

[ctuna]

Are you sure you have a strong battery .
The IBS system can turn stuff off with a weak battery.
(Try putting a slow full charge on your battery and see
if it goes away for awhile)Measure the battery in the
morning before first start it should be over 12 volts and to
be healthy more than 12.4
Read about IBS in first electrical PDF.

There are three basic types of sound systems with an e90
stereo (no amp no tweeters)Hi Fi 6 channel amp 6 major
speaker locations , Top Hi Fi also called Logic 7 9 channel amp
with a fiberopic connection between the Head Uni t and Amp.
Sound systems means speakers and amps not head units.
If you have bluetooth phone , Sat Radio or DAB those are seperate
modules on the Most Bus which when they go bad can take
down the sound .

Its common for the amp area's to be subject to water leaks.
Then the amp will drown.

If the power on the head unit is going in out then there has to be
some kind of power problem.
Is the power going in and out on anything else?


electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU


BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/showthread.php?t=641323
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...4&d=1278871872

[madgerald]

Thanks for the reply - I will check the links out...

The only other electrical fault I can think of is a lamp warning light even though all lights are working.

Could it be connected?

Bill

[madgerald]

Originally Posted by ctuna

Are you sure you have a strong battery .
The IBS system can turn stuff off with a weak battery.

What does IBS mean?

[ctuna]

Intelligent Battery System .
But it could really be called the Infernal battery system.
This is a sensor and processor that measures the state of charge
of your battery . If it gets to low it will turn off what it deems to
be unnecessary loads like the entertainment system.
Another symtom of this thing working is if you are sitting in your
car listening to the stereo with a low battery it will turn the stereo
of after a short amount of time and you will wonder why?


What it does is described in the first electrical pdf.
please read it.
If you don't know about it you will chase your tail on a lot
of electrical issues. Its known to cause ghosts in the system.
For this reason when BMW gets a car in for repair they throw
it on a charger right away.

Also there was a recall on the power cable to the fuse panel in
the cabin for bad contact. But if you had that all the lights on
your dash would be going out.

[madgerald]