BMW MOST BUS DIAGNOSTICS AND REPAIR, E90 EXAMPLE
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- เผยแพร่เมื่อ 25 ส.ค. 2024
- HERE I will show you how to properly diagnose bad MOST bus unit and successfully bypass it!
Standard problem-no sound, bmw dealer diagnosed bad amp and wanted 1900$!! All was fixed in 5 minutes under 30$. Bad unit turned out to be sat tuner module, which was bypassed. If you don’t listen to xm radio you don’t need the unit, if you do - buy another xm unit.
www.bavlogic.c...
fiber optic bypass loop jumper:
amzn.to/3HrYwuh
Others have already said it but THANK YOU.
It's beyond me why this seems to be one of the only videos explaining the system in simple / understandable way.
Saved me hours of headache in minutes. You have my gratitude
Thank you, good that people understand how much money and hassle saved!!! Yes we are talking about thousands at the dealer for such problem
@@Logic7repair Hello! Can the sound turn off due to a broken combo box?
This video fixed my 2006 e90 330i pre-lci that hasn’t had sound for about a year. I was inches away from buying a new amp but thanks to this man i didn’t. I simply bought the part listed in the link in the description, plugged it in less than 10min and heard the classic BMW ping. What a guy. I appreciate it!!
Thank you!!!! I was able to stop the most annoying tapping/popping, occasional buzzing because the SAT unit died. I am so eternally grateful!!!
Yep, good job! very common problem after CCC unit of course.
Thanks so much for this info! My 2006 650 had a radio cutout/ SOS green light intermittently. The dealer wanted $2200 for a new head unit. Thanks to you I spent 1 hour and $8 on a bypass loop. It works fine again, with no unusual indications.
Ccc only 2200$ from dealer? They quoted our client 4500$ last time
After so many hours researching my SOS malfunction and stereo problems I found this video to be unbelievably helpful!! Thank for for this and also for taking the time to make a Diagram!! Great vid. Many thanks!!
THANK YOU, SO MUCH, SIR!
This is the most helpful, most straight forward BMW DIY video on TH-cam!
One rat got inside of my 2008 335 e92 and the rat ate my harness from the glove box fuse box, you have not idea I had to remove the glove box and fix all the harness, days trying to find and doing bypass to the amplifier, till I found your video, the connector on the driver side was disconnected 🤦🏽♂️ I bought this car as a project and the previous owner or mechanic leave it disconnected, thank you so much sir!
Great video, thanks for sharing and showing the MOST diagnostics port under the drivers side. Many sources don't talk about this connection point.
I have a 07 e91 wagon I just bought and was getting a sos on the dash, I watched so many other videos and not one of them mentioned the port under the dash. I looked at it and the loop there was missing. I put a most loop on and it cured the problem!! thanks a lot for this video
I reviewed a few other video about this topic. Your explanation of the the fiber network was excellent. I was able to isolate my problem. it was the sat radio module. Thanks you save me $$$
I have a 2008 e90 335i. I’m trying to figure this out on mine. That little red led light won’t blink on any of my unit connections. Also my satellite is MIA. Would that be a reason why my audio isn’t working?
Hi, I have a problem when I checked all fuses, optic fiber has no lost connection, and amp steady yellow. Still no sound. I have Logic 7 amp and most module. Any ideas what else I can do?
Hey my friend I don’t know if you still working with this or not but, in my case I have a328i 2011, and is working perfect but sometimes is just not turning on when the car is on. The radio can turning on in like 10 or 15 min by it self . And another thing that i see is , if my phone has the Bluetooth on never get the radio ON, I check the fiber and is blink it on
What if you did put the loop in and you still don’t have the blinking light under the dash?
Just did this today, got my most loop of Amazon for $6 and $21 for shipping to SA, bypassed the mulf, works perfectly.. thanks mate.
OMG THANK YOU SAVED ME SO MUCH TIME AND MONEY
AND WAS. ABLE TO FIX PROBLEM WITH MY DONER Car!
You’re welcome!
So what if your speakers just pop but sound come in just popping and cracking
the fiber optic that plugs into the amp isnt red what could be the problem head unit i suppose 0:38
Can you use the termination plug as a bypass loop to test the potential fix?
what if my fiber optic that goes in my radio unit is removed?
How to connect extra cooling on that thing on the left side in front of stop light
i have no lights on the optical to the amp. can anyone help me please
I have a 2007 750i and my subwoofers don’t work. My side speakers work but not my subs under my seat. It turned on randomly for like 30 minutes but that was it
What does it mean if there is the orange light but it’s solid and NOT blinking?
I have a clicking or popping sound coming from my speakers. It doesn't matter if the radio is on or not, the car can even be off and still popping sound coming from the speakers. The only way to make it stop is to unplug the and amp. I have replaced the amp but the amp is good. So I was watching your video about the most bus and when i checked my fiber optic cable going to the amp, it isn't red. What could that be? Sorry i'm not very versed in electrical stuff at all! Lol
Jimbo Bannister I have the exact same problem, I don’t know what to do
@@ethanflav2471 well I finally got mine figured out. I took it to my bmw guy and he wen't thru the entire system and finally found it. Ended up being the satellite dlp module gen2.5. Which is in the middle of the trunk under the "lid" that raises up. It's very easy to change out, just plug and play and doesn't have to be reprogrammed. Their expensive from the dealer but used ones are just over $100 on ebay. Glad to finally figure it out, hope this helps man!
Jimbo Bannister thanks so much dude, I’ll get right on it
Isn’t it what’s in the video what failed?
@@Logic7repair that's not what mine was doing, I had a different issue
This video helped me out a lot… thanks mannnn
Hi! Please help!!
On my 06 330, the light is on at the amp, but off at the Bluetooth thingy in trunk and off on the wire under the steering wheel…
I haven’t been able to test the voltage due to not having the tool.
So that means it’s the amp that needs replacement???
Why no light coming from my amps fiber optic wire to the telephone module?
Hi! My radio stopped working and the SOS light came on on my BMW 335i E93.
In my case the AMP was broken so I connected a loop. After this the SOS-signal turned off but still NO sound from the radio.
Any idea what this could be??
I have a ‘06 330xi (e90) and have this same exact issue, the light at my tcu is blinking (I don’t have a sat tuner), but the cable under my dash has no light. I disconnected the cable at my tcu and connected the fiber optic loop, but the light is still off under the dash. Any idea what else it could be? So basically I only have the amp, tcu and block off connection under the dash. Cable at the amp and tcu are blinking, but the block off is dead. Fiber optic loop on tcu cable doesn’t fix issue and block off connection is still dead/no light.
do any one know the part number for that lil tool I have 2 from BMW but they don't fit
Wer is the fuse located for the amp my amp haves a red light thers no Amber light can you help please basically I have no sound I had sound yesterday we had down paw last nyt and I noticed water near the amp whats got into the car after 9 hours of rain I need to no why red light and not Amber
I bought a used 2006 330i and the dealer I called said it was prepped for the satellite tuner when it was originally sold but when I went to diagnose why I didn’t have sound the module wasn’t there connected to the TCU it was completely absent, is the SAT module necessary for the Audio to come out? Before I purchase a SAT module I’d like to know. Is it possible to make my car that’s coded for it work without it? Ps my amp has a yellow light, all fiber optic connections are red, and the fiber optic loop I connected to the amp and the TCU didn’t bring my sound back.
Hi i have bmw 330d m sport 2007. I have sos malfunction light on the dash. I checked the boot theres only TCU unite. Theres no satellite unit and no amp unit in the boot. Hope you could help. Thanks
Question - Recently bought an 08 528i. Sos malfunction on along with aux & cd greyed out, with no sounds from the radio at all but I can hear the radio fan on & sometimes slight static from passenger side speaker. When I unplug everything I get a red light on the amp connector, plug that in then light moves to satellite, then to the telephone control module but when I check the head unit connector in my glove box I have no light from it at all? Tried bypassing each unit one by one but got nowhere. I checked all fuses & they were good. Any suggestions ?
I replaced my logic 7 with a used one and still doesn't work, does it have to be decoded? Thanks
Can i use the termination loop as the bypass for the satellite module? Just to diagnose before i buy the actual bypass loop
P S of course
Hi i changed my MULF with MULF2 on my E90 (MULF has bluetooth issues) after i set MULF2 it work perfect for two months now when i trying to connect my phone with bluetooth on bmw professional radio it stuck on "bluetooth devices pairable..." and cannot connect with my mobile phone
Mulf2 failed, it’s common
Awesome video, I went through this diagnosis as much as I could, there is no light in my amp, I’m guessing that means the amp or the line is bad. However, the radio does not even power on. I have a non idrive so just the regular radio. Nothing in the screen, I checked the connection with a volt meter and got the proper 12V. Also there is no satellite module in the back of mine, just the phone module. I’m assuming that some cars don’t come with it as I don’t even see the loose wires that would indicate that there had been one installed. How would you bypass without the satellite module. I get the sos and caution sign on the dash upon startup. I drive a 2008 BMW 335i E92 with the logic7 setup.
Same, and there isn’t much info out there. I read that the sat is integrated into the head unit for some models. Mine is a 2010 with the cic nav. Did you ever fix this?
@@JESUSWARRIOR11 not even close, still have no sound even today
@@Mr77Trojan I have the same issue but Idrive, have you figured it out ?
@@JESUSWARRIOR11 have you fix it ? I have the same issue
@@gatiyovideo Unfortunately no, I’ve tried everything except having an aftermarket line and system installed. I changed the AMP and got a response from the amp but still no audio. Changed the Radio itself to another OEM e9X radio.. nothing.. installed an EONON head unit… nada.. ran the fiber optic loop… still null.. just been rocking a small Bluetooth speaker ☹️😓
I believe my 2010 e93 has the sat integrated with the head unit. So I see the red light at the connection to the amp. And the next module in the trunk after the amp is the TCU and the fiber optic going to the TCU doesn’t have the red light. So does that mean my amp is bad?
I have red light blinking even under the steering. Is the existing loop not working?
Thank you for your video, I have a yellow flashing led on my Amp, but the amp is not outputting a infa red signal to the next MOST module. If I remove input infa red input to the Amp at the processing board then the amp starts pushing out a output signal on the output infa red. If I loop out my Amp on the MOST bus all over MOST modules work?
My radio sounds but it won't turn on by itself with the car, there is some problem with the communication to the amplifier when I scan the car, any ideas what could be wrong?
also, there is no "Computer" option, steering wheel controls don't work either
I followed all the connectors on my 2006 330i and they all light up but I’m still not getting any sound from my radio or door chimes. I checked all my fuses and they’re all good. I’m not sure what to check anymore.
I have a 2006 BMW 330i with door chimes and seatbelt sounds.. But no sound on my idrive CCC navigation unit. I have a new display
You have CCC navigation unit ?
So my e92 sound just went out. I can see that the fiber optic cable lights up when I unplug it from the LOGIC7 Amp. However when i plug the FIBER OPTIC back in, the Amp's internal troublshooting LED is RED, not Orange. Does that mean the AMP is bad, or is the head unit bad thus not providing signal to the amp? I am not sure what the RED LED means, its not orange so I know something isn't working. I think maybe the issue is the head unit, but I cant say for sure, bc when I Loop the TCU unit, the Fiber Optic Loop for the Termination Loop, blinks fine. Please any help would be appreciated. I've been at this for a week now, the Head unit, powers on, ejects CDs just fine. I have also checked all my radio fuses, I have reset the radio by holding both EJECT and POWER. nothing is bringing sound back not even the sound when you open the door with the key and headlight on.
Hello my amp light blinking my telephone magual blinking also but my satellite tuner is not but then I put the bypass wire on the telephone magual then the satellite tuner blinks still have no sound
i have no blinking light to the amp
God bless you bro 💯
what is the correct term for the loop? whats the correct term to tell the sales associate?
What if yellow light is not blinking ? But still same issue is present?
If the amp is bad would the red light to the telephone module work?
No, first node is the amp, so if amp is bad tcu won’t get red light signal. Bad amp in rare cases can still transfer red signal but you won’t see yellow led in it
Only my head unit blinks red. What does this mean?
I have an Audi issue with my 07 E90. I ran the diagnostic per your video. However, the red fiber optic has no break and it goes out and back to the head unit without breaks. But I still have no sound!! I don’t have navigation. What would be the reason for no sound? Door/seatbelt chime is super low and it comes from the dash. Please help!!!
did you solve it?
I have a 2008 E93 with the "SOS call system malfunction" with no radio or sounds for the key, lights, seatbelt alarms. I have red blinking fiber lights at the telephone mod and to the Satellite mod, no blinking lights at the amplifier or under the dash. Tried bypassing the Satellite with jumper, this didn't help. The Christmas lights sequence does match what you diagramed. Can someone please advise?
I'm having same.issue
I accessed every module and unhooked each fiber line one at a time, found the MULF as bad using the jumper. I was told the sequence of programming my be different model by model. Ordered a used MULF on eBay based on the module labels. It was a plug and play. Good luck.
Hello,
Asking if you may know, if any of my fiber optic cable at the trunk is broken/cut, let’s say from the telephone module, will I still be able to use the bypass kit for the other fiber line to run the system normally without the module with the broken/cut fiber optic line?
What if the radio wont wake up from its sleep mode? Does it have anything to do with the fiber optic? Its intermittent.. Sometimes radio wakes up sometimes it takes time
Is this all done while the radio is on?
Would the steering wheel connection be on the square on the steering colum for an F30 3 series?
No they don’t have ir
I have problem with SOS failure and BT not working. I connected second TCU unit but still not working. In ISTA i have 3 errors : 1. VIDEO 2. CD Charger 3. Telephone. How i can try to fix it?
Best explanation I have seen so far, thank you.
So which ever one isn't blinking is the broken part?
What if your stereo doesn’t work, checked all fuses, took stereo out and it works in another car, no power to the radio or sound from it. Could a faulty mulf module/amplifier in the boot, cause this problem?
maybe is faulty ccc or nbt unit? this was my issue
@@farqueue I scrapped the car over the issue and got a newer 120d my friend, thanks for the reply though
What do I do if I’m missing my satellite radio?
What if everysingle one of my lights are lit up but i still have no audio and theres no sos light too
Hey I have the same problem did you figure it out ?
What if you have no power to the headunit/amp/etc... YES the fuses have been checked...
run a new wire
Must be the fuse, check diagram and recover the power line
I have the same issue did u figure it out ?
How do I bypass TCU if it’s bad?
Why does it on mines it has a white light
will this stop communication with OBD?
what if my head unit is not giving any signal to the AMP? do i need to replace the CCC unit?
@@thekiller500099 head unit works overall?
@@Logic7repair yuppp i drive works just no chime, no sound no rings
I have no base but otherwise the stereo works fine. Checked all the red lights and they all work. I don’t have the satellite radio. And it seems the phone is first from the head unit, followed by the amp then end. That’s what the red lights showed me at least. Amp has solid yellow light. What else should I check?
It was the amp…
Mines stop at the cd/dvd unit in my 6 series what do I do
Amp blinks yellow (logic 7) all the fiber optic plugs are blinking red except for the one under the steering wheel. Radio buttons work but no sound or chimes any suggestions? Tried to bypass the sat module and other one even though the fiber optic connections were blinking red and still nothing.
Means no commutation between last module to the steering wheel point
@@Logic7repair I just tried the jumper loop again on the sat module after putting a different amp in I now have a the blinking red under the dash but still no sound , this is a headache 😂
Thanks so much for such a detailed video! My subs and mids have not been playing for a while now and instead of just spending $1000 or more to replace it, I am going to use this video as an example troubleshooting method. Because I do have power at the head unit and highs, should I approach this differently? Any clues or assistance will be certainly helpful.
Did you ever figure this out! I have the same problem
Curious as well my subs go in and out mostly out only highs working for me. Any help is appreciated
@@jusmoney4320 figure it out? Same issue here
Subs can be bad as well
how do you check the red light?
Nice. Great job!
I have the red light all the way to the one under the dash but my sound system still won’t work. Is there a fuse I can try? Or is this something else
Amp has yellow steady led?
thanks for saving me money!!!
Question - what if you don't have the satellite tuner? Would you still use the jumper? I have intermittent radio on/off, the SOS light comes on/off, and the bluetooth stopped working (gives a high screeching sound when the phone is connected until the phone drops again). Would the telephone module need to be replaced if I don't have a satellite tuner?
Any unit in fiber optic bus can fail, sat tuner usually goes bad, but so any other can go bad
My car has signal everywhere and I have 1 looped connected signal goes all the way back to the front termination loop. And my idrive works perfect but I have no radio sound or door chimes. Need help!!!
Hey did you figure it out I have the same problem
On my BMW 328i 2010 the amplifier is not on the trunk, could it be inside the dash?
3 levels available:
-stereo option no amp at all
-676 hifi amp in the trunk no fiber
-677 fiber optic amp in the trunk just like in the video
So I found out that my car has no amplifier, but I got a black amplifier from another BMW 328i. I was thinking in installing in my car, is it possible?
I have tried everything. I have bypassed or tried to bypass all of the components. I still get an sos issue
You are doing it wrong, you need to see if signal comes back to head unit. It starts from head unit and must come back to head unit, in your case it’s not coming back to HU
The problem I'm having is that when I start my car, sometimes the volume works and sometimes it doesn't. After I installed my aftermarket Android head unit, I didn't get any sound and the SOS light popped up. I bought a MOST fiber optic interface for the head unit which converts the fiber optic into 2 RCA inputs to the back of the head unit. This provides sound but only sometimes. If I don't hear sound, I have to restart my car a few times and then the sound comes on. Any advice on how to fix this?
Where did you get with this? I have same issue.
I have nav with individual sound but not logic 7.
Also no sos malfunctions of any sort
@@mvazac7298 Hey, I actually figured it out and made a video with the details in the description: th-cam.com/video/Qo9wvzU1L_s/w-d-xo.html
Excellent well done thank you
Thanks man
I have the MOST bypass loop and attempted to diagnose this but am coming to a blank. Amp has yellow light that blinks, confirming amp is functional. Checking all connectors from amp to Bluetooth to sat radio all have the red light. Using the bypass loop or having the connector plugged to the sat radio module, the final termination under the dash has no red light. Any ideas?
Alex Kaczmarek , red light must be present at the connector near steering wheel, something in broken or optical line damaged
Mine shows all lights on? What could it be
johann orozco mine too
My e90 2011, showed that SOS light this morning on my dashboard when I inserted the key in the ignition. When I tried to push to start the brake felt hard and my car wouldn’t start. I kept trying it till finally it started. Can the SOS be a reason to why that happened?
Iliana L , SOS can’t be related to no start issue, no start like cranking but no start or barely cranking like low battery? SOS message is related to TCU unit failure in the trunk most likely or some other unit on fiber optic bus.
Can I pay you to diagnose my car? Dealer said the amp needed to be replaced... do you live in the NYC area?
What do you do if there is no red light to the amplifier. I should add that I had the complete interior out of the car including the center consul. After putting it back together I have no sound at all and there is no light at the amp.
Means no light coming from the head unit, check it from the head
@@Logic7repair thanks after some thought that’s what I came up with. But the problem is that this whole car has came apart and put back together. So I am thinking I might of miss a plug somewhere. What would be really helpful would be a clear wiring diagram that shows the deck to the amp so I can make sure it’s all plugged in correctly.
So what if my first wire (the only in the beginning of the video) has no red light
It starts from the back of the head unit originally, check it there and find out where it goes. If no light in the back of the head, it’s the head unit
@@Logic7repair I’m putting an aftermarket stereo in, my fiber optic cable isn’t connected to anything where should I put itv
Hi when i disconnect plug from satellite unit and plug it back in the radio comes on until i hit a bump in road. Then it goes off. I bought the loop today assuming the satellite unit has something broken inside.
Yes sat unit is bad
@@Logic7repair yea i don't use satellite anymore so loop will help.
I have no light coming from the setallite tuner, or the one inside under the driver side. The amp an the one to the right of the setallite unit both have red lights?! Help!
that should mean the module to the right (telephone module) is bad. put the optical loop onto the cable connecting to the telephone module and see if it works.
My brothers BMW is missing the termination loop on the last wire shown on the drivers side. Can you use a jumper loop on it? Or does it have to be the one shown in this video? (the termination loop)
xxLoveKevaxx of course it must be looped just like any other MOST port or connection
I have a 330i e90. My speakers had a large 100db screeching noise, 15 min later it stopped. I have 0 audio on anything (Inc aux) would that be my logic 7 Amp that's busted? I also don't have a SOS sign showing up... so I'm confused on what to do.
Most likely the amp, but I can’t diagnose it properly over the air…
The same thing happened to me… did u find a fix?
my rear speakers dont work on my coupe any ideas everything else works just no bass
I'm on the same boat , so far no info anywhere.
Figure it out?
@@yotaismygame same issue figure it out???
Did u figure it out. ??
@@ferng9405 I believe it was the logic 7 amp. Bought a used one problem solved. Water can get down in there and fry it.
I have a 2008 series 5 the sos light on & aux plug work when it want to 🙄 should i i do this ?
Most likely MULF unit is bad, we can fix it.
I’ve got no red light on any connection
brett baker light starts from head unit, find out why it’s not there
Did u figure it out ?
So i bypassed the tcu and the red light is now flashing at the wire under the dash but still sos error and the amp is flashing yellow light, do you know what the problem could be? The only thing after the under dash wire is the radio, could the radio be bad?
P S that’s happening to me, did you figure out how to fix it?
This is the first time I’ve dealt with this, I got the SOS randomly after hitting a bump I suppose. I checked every optical loop in this video and none of them are flashing red or any color at all. I tried the bypass loop on all of them and nothing. Idrive screen is black, no music, radio, door chimes etc, if anyone knows what I should do or look at or if I’m doing something wrong please help. (2008 335i w logic 7)
Head unit produces fiber light, so it’s lost somewhere obviously, you need to
Find out where. It’s gotta be flashing at least at first receiving unit
@@Logic7repair Do you know where the unit is? I looked at the one under the steering wheel, and 3 in the trunk. Could it be a fuse or CCC as well? because it all happened after I hit a pothole so I'm guessing something came loose somewhere
Can I send my logic 7 to you?