[Murf]

So I have the dreaded SOS malfunction error and have lost all sound in my car (chimes, radio, backup) as well as Bluetooth functionality. The Logic 7 radio and nav work fine and it shows bluetooth as active but turned off. From reading the forums it seems this is a common TCU failure.

I purchased a used and known working TCU off of ebay (same firmware, one month newer than mine) and installed it but I am still getting the SOS malfunction error and no sound. I know the TCU will need to be coded to my cars VIN but I kind of expected the error to go away with the replacement unit. What am I missing here, when you replace the TCU do I have to code the new box to make the error go away?

Note to mods - I have cross posted this in the Coding and AV forums..

[PichaDis11]

Coding is needed to code out the SOS function. It will no longer be operable with the new to you TCU module. I'm not sure what head unit you have but you may try to reset the radio by holding down the power button for about 25 secs. It should pick up the TCU after restarting and issue a reset on the MOST Loop. Hope this helps.

[ctuna]

Does your sound work if not it could be the amp.
You could bypass the TCU and satellite radio module, if you have one on the
Most Bus to see if your sound comes back to verify its not
the amp.

[Murf]

Everything works or seems to but no sound. Going to pick up a most bypass tomorrow and start testing. Didn't think about the amp as potential issue, does it throw the same sos error if it dies?

What's the consensus on the TCU repacement, should it require coding to have any effect?

[ctuna]

Any break in the Most Loop can make all the modules on the Most BUS look bad
.

[Murf]

Thanks ctuna, I didn't know that. I am going to pick up a most loop isolator today and try to figure out which module is bad. Hopefully it is either the TCU or the sat box and not the amp.

I noticed today that radio and nav are working fine (no sound) but that Sat and Aux are greyed out on the L7 headunit, does this help pinpoint the issue?

[ctuna]

Aux comes from TCU and Sat comes from Sat do you think there
both bad? Most Bus problems are Hard because if one thing goes
out everything else looks bad.

[Murf]

Originally Posted by ctuna

Aux comes from TCU and Sat comes from Sat do you think there
both bad? Most Bus problems are Hard because if one thing goes
out they everything else looks bad.

See my update in the first post. It was the sat module, I actually had another TCU on hand to test, both were fine. My car uses MULF for BT and AUX, the TCU is only handling SOS. You're right, the errors point you in the wrong direction. Only thing to do is remove them from the chain until the problem goes away.

[ctuna]

It would be nice if you put that response at the end
in the first place instead of making things look all out of
sequence.

[Murf]

UPDATE - It was the Satellite module, I purchased a most diagnostics jumper from the dealer and when i jumped out the sat system everything came back. I don't even use sat so no loss for me, I just used electrical tape to hold the jumper in place permanently, no codes that i can see although sat is now grayed out at the head unit. One other thing to note, the jumper does not fit the 335i as is, it needs to be cut apart and the center piece is all thats used. I initially flipped out that I just drove 1.5 hours round trip to pick it up and it didn't fit at first.

To those that have SOS malfunctions, it's not aways the TCU although the error does point to that. Avoid the dealer, buy yourself a jumper and go through each component to figure out which one is causing the problems.

[JStang]

Originally Posted by Murf

UPDATE - It was the Satellite module, I purchased a most diagnostics jumper from the dealer and when i jumped out the sat system everything came back. I don't even use sat so no loss for me, I just used electrical tape to hold the jumper in place permanently, no codes that i can see although sat is now grayed out at the head unit. One other thing to note, the jumper does not fit the 335i as is, it needs to be cut apart and the center piece is all thats used. I initially flipped out that I just drove 1.5 hours round trip to pick it up and it didn't fit at first.

To those that have SOS malfunctions, it's not aways the TCU although the error does point to that. Avoid the dealer, buy yourself a jumper and go through each component to figure out which one is causing the problems.

I am hoping mine is just the SAT box as well. I have been trying to chase down my issue which is exactly what you are describing for a while now. My SAT box is greyed out now even with it plugged in so I'm hoping it's the issue.

I will pick up a jumper after work and check back in with the solution.

[JStang]

I hooked the jumper up to the satellite radio box and the sweet sound of audio through the speakers was present once again.

[Murf]

Ain't that grand? $30 fix for the win.

[JStang]

Originally Posted by Murf

Ain't that grand? $30 fix for the win.

Yeah, now if I only would have done this first instead of buying a TCU, taking it to the dealer for $140 diagnostic fee and being told I needed a new CCC ($275.00).

I am going to contact the dealer to see if they will reimburse the diagnostic fee since they totally dropped the ball.

[Murf]

Yeah I got hung up on the SOS error code and bought a used TCU also. I was pretty pissed when that didnt fix it but I was able to return it.

There's lots of threads each with little tidbits of info on these problems, hopefully our experiences will help someone avoid the pain of reading hundreds of posts trying to figure out which are relevant.

Next up is VCG, clutch and front brakes/rotors. Car is becoming a rolling shitshow at 82k, was hoping to keep it to 120 or so but not sure I am going to make it.

[intel1]

I had my Rear right Power Window Regulator replaced and right after that i start getting
SOS error with line through it and phone receiver icon.my car model is 2006 330xi.
I did do following coding so far.
TCM_ALIVE_MONITOR -> nicht_activ
TCM_ID_MONITOR -> nicht_activ

BMW_ASSIST_RAD2
nicht_aktiv
BMW_HOTLINE_RAD2
nicht_aktiv
Radio, blue tooth, voice command all are working, just got icon on display. SOS ERROR in yellow color.
Can u please tell me what else i need to change.

[SlimE92]

Originally Posted by Murf

UPDATE - It was the Satellite module, I purchased a most diagnostics jumper from the dealer and when i jumped out the sat system everything came back. I don't even use sat so no loss for me, I just used electrical tape to hold the jumper in place permanently, no codes that i can see although sat is now grayed out at the head unit. One other thing to note, the jumper does not fit the 335i as is, it needs to be cut apart and the center piece is all thats used. I initially flipped out that I just drove 1.5 hours round trip to pick it up and it didn't fit at first.

To those that have SOS malfunctions, it's not aways the TCU although the error does point to that. Avoid the dealer, buy yourself a jumper and go through each component to figure out which one is causing the problems.

Please direct me to said jumper I'm in need brother. Thanks

[Murf]

Originally Posted by SlimE92

Please direct me to said jumper I'm in need brother. Thanks

Sent you a DM my man.

For those looking for a jumper this is what you want, dealers will carry them for around 30-35 bucks. You need to take it apart and only use the center loop piece, it will not fit our connectors as is (its for the 7 series).

https://www.ecstuning.com/b-genuine-...h/61136917541/

[SlimE92]

Originally Posted by Murf

Sent you a DM my man.

For those looking for a jumper this is what you want, dealers will carry them for around 30-35 bucks. You need to take it apart and only use the center loop piece, it will not fit our connectors as is (its for the 7 series).

https://www.ecstuning.com/b-genuine-...h/61136917541/

Thanks man I appreciate it heavy.

[intel1]

Guys i need help with this error. I finally was able to pull error code for my SOS issue.
I used DIS to run diag for my 2006 330xi and this is what showed up.
TCU-A369 TCU GPS AERIAL, OPEN CIRCUIT.
Please guide me in the direction so i can do a troubleshooting for this issue. I really appreciate it.

[ctuna]

http://www.e90post.com/forums/attach...2&d=1260829447

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

I would check and reseat connections at the TCU/MULF first the antenna
is in the sharkfin I think.

[schwing]

Originally Posted by Murf

Sent you a DM my man.

For those looking for a jumper this is what you want, dealers will carry them for around 30-35 bucks. You need to take it apart and only use the center loop piece, it will not fit our connectors as is (its for the 7 series).

https://www.ecstuning.com/b-genuine-...h/61136917541/

I got a generic MOST loop jumper on eBay for under $10. It helped me figure out which module/connection was causing my SOS malfunction.