[vitez180]

I have SOS light on the dash and ISTA shows instrument cluster: no message (telephone). The radio usually works except a couple times it will shut off for a few seconds and then come back on.
I attached a picture of the ISTA fault code

I have a clicking sound coming from the speakers, non stop, no matter if radio is on or off, it clicks kind of from front to back like tic toc kind of repetitive thing.

I have the HiFi speaker option. The first time the radio cut out is when I turned the bass dial all the way to the top, not sure if its a coincidence or not. I usually don't listen to music loud or anything, I just recently got the car and testing out the sound. I don't have iDrive and when I try to pair my phone by holding the button on the steering wheel, nothing happens. I dont think the MOST loop trick would work since this doesn't have MOST since its only HiFi not logic 7?

[ctuna]

The Radio and the Amp are on analog connection in the Hi Fi system
however the options like hands free phoned and SOS require a least
a TCU on the Most BUS.
And the TCU can take contol of the head unit .
In Europe there are some cars without Most Bus but not in the US.
In addition in every year but some 06's the alarms comes through the
stereo so the Head Unit and Amp are never really off.
The Head units display is just muted (no lights ) but the head unit
is never off.

SOS error means the TCU is kaput .

[vitez180]

Originally Posted by ctuna

SOS error means the TCU is kaput .

Would that be why the AUX and USB port don't work? I just tried connecting a MOST bypass on the front of the TCU, the clicking stopped, but AUX still doesn't seem to work.
I guess I would have to replace the TCU for that to work.

[ctuna]

If you have USB that means you must have a Mulf 2 Hi or
a Combox. If you have a TCU the mulf 2 hi is underneath the
TCU. When you have USB , option 6lf, the usb cable and aux
cable comes from the Mulf 2 Hi.

Bluetooth is handled by the Mulf 2 hi when 6fl option is installed
as well as aux and usb.

http://www.e90post.com/forums/showthread.php?t=1181654

Both the mulf 2 hi and the tcu have there own most connections.
Anything that is optically bypassed won't work .



If you have Inpa it's a good idea to run functional jobs to see what is says
about the modules. Plus in the block diagram in Ista plus might be able
to tell you something.

It's a good idea to state the year of your car because options
and modules can change by year.

diagnostic manual ista/inpa
https://www.google.com/url?sa=t&rct=...xo19teM9vkTF-C
https://www.google.com/url?sa=t&rct=...7x8H3pN8h1fMuF
https://bimmerprofs.com/diagnostics-inpa-part-1/
https://www.google.com/url?sa=t&rct=...lkXEhlQYy4i9Nb
https://www.bimmerforums.com/forum/s...-P-actually-do
https://www.bimmerfest.com/forums/at...1&d=1590283589
primary links
file:///C:/Users/ctuna/AppData/Local/Temp/INPA%20Tutorial%20Quickstart.pdf
file:///C:/Users/ctuna/AppData/Local/Temp/Handy%20E9x%20References.pdf
https://www.e90post.com/forums/showthread.php?t=1681573
https://www.nathansbmwworkshop.com/b...or-dean-videos
ista problems
https://www.e90post.com/forums/showthread.php?t=1661945
https://www.e90post.com/forums/showthread.php?t=1581663

[gbalthrop]

Originally Posted by vitez180

I have SOS light on the dash and ISTA shows instrument cluster: no message (telephone). The radio usually works except a couple times it will shut off for a few seconds and then come back on.
I attached a picture of the ISTA fault code...

Since you have ISTA working, I would suggest viewing, and Saving ScreenPrint of, (1) "Control Unit Tree" and also (2) "Display Fault Memory". If you can attach jpg's of those screens here, someone can help. As you should know, Control Unit Tree shows ALL Bus systems in the vehicle, and the Status of EACH Module as to whether OK, Fault Present, Can't communicate, etc.

Please also clarify the STATUS of your various "Audio Inputs": FM, CD, Aux, USB, as OK, Intermittent, NONE, etc.

I presume the vehicle in question is as per the ISTA Header?

George

[vitez180]

Finally got a chance to get back to it and replaced the MULF2 (Bluetooth module), under the TCU, and now my USB and AUX ports all work. Mine is a 2008/07 production date with the USB/Aux option.

Thanks everyone who helped. Not sure if there's a Solved flair I'm supposed to tag or something.



One of the pins fell out when I pulled out the connector from being rusted out. The outside looks like it has corral growing on it.