Bmw speakers not working

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BMW Radio No Sound From Speakers

In this guide, we take a look at how to troubleshoot BMW radio issues yourself.

Getting your BMW radio and sound system diagnosed by the dealer can be very expensive. Due to the BMW entertainment system's complexity, many car mechanics are unfamiliar with or know how to fix the BMW radio problem unless they specialize in BMWs.

This article is meant to help BMW owners and mechanics who are trying to fix BMW radio issues.

Understanding the BMW radio setup

MOST stands for Media Oriented Systems Transport and can connect up to 64 bus systems in BMW vehicles in a ring configuration.

Because BMW audio components are configured in a loop, if one module fails, everything stops working. MOST networks connect multiple devices such as the amplifier, telephone unit, satellite tuner, iPod interface, Bluetooth hands-free module, etc.

Advantages of MOST Bust network

  • Simplification of wiring,
  • Reduction in the number of cables needed
  • Transmission of complex data
  • Flexible configuration

MOST Components

This is a list of components that can be part of the BMW MOST network. Your BMW will have a few of these, depending on the options that came with your car.

You may have anywhere from three up to eight components.

  • CIC / CCC - Located in the dashboard, below the climate control
  • CD Changer - Integrated with the CIC/CCC or in the glovebox.
  • Telephone - In the trunk, left.
  • Amplifier Logic 7 - In the trunk, left.
  • Satellite DLP Module - In the trunk, left side.
  • Bluetooth Phone Module - In the trunk, left side.
  • SPS Speech Module - Located in the trunk, left side
  • Voice Input Control Unit SVS - In the trunk, left side.
  • ASk Head unit - Head unit in the dashboard
  • TCU telematics control unit - In the trunk, left side.
  • Antenna tuner or digital tuner - Located on the left side of the trunk or behind the rear seat.
  • Headset interface - Located left side of the trunk.


Here are a few symptoms you may notice if one of the MOST components fails.

  • Malfunction message on the iDrive screen
  • BMW radio works but has NO sound audio
  • SOS malfunction error on startup
  • Bluetooth phone not working
  • Crackling From Speakers could be issue SVS or TCU module
  • iDrive keep switching to the home screen

Common Issues

Possible problems that can trigger fault codes in the MOST module.

  • BMW Radio Works but NO Sound
    This problem is caused when the optical loop is broken. Even though all the modules function and seem to work properly, one of the modules listed above is defective or not turning on. To find out which module is defective, you can use a female fiber optic loop (also called a lollipop) and bypass all the modules one at a time. When you bypass the defective module, you will get sound from your BMW speakers. The telematics unit and the speed module located in the trunk are often the culprits.
  • Cracking from speakers
    A common problem is cracking, usually from the front speakers. The iDrive may also randomly restart and go to the home screen. The Bluetooth module sometimes causes this problem. Try performing a MOST reset.
  • SOS malfunction on startup
    The airbag or SOS light comes on when there is a problem with your BMW audio system. If you are getting the SOS malfunction on startup, it can be because the telephone module recognizes that you won't be able to make a phone call in case of an emergency. You can scan the airbag (SRS) module to verify the fault code. The code will usually point to an issue with the radio or telephone module.
  • CIC / CCC
    If your BMW is not turning on at all, there is a good chance the CIC/CCC head unit is defective and needs to be replaced. Learn more about BMW iDrive radio won't turn on issue.

Troubleshooting Tips

bmw battery in trunk

Here are a few troubleshooting steps you can follow if you are experiencing problems with your BMW radio and audio system.

Disconnect Battery

Disconnecting the car battery for at least 12 hours will sometimes reset the failed MOST component and fix it. Leave the battery disconnected overnight.

This will force the components to reboot. Another way to reset BMW MOST is by using a BMW diagnostic scanner.

Read Fault Codes

If you are experiencing problems, a good starting point is to read fault codes from the MOST module.

If any code shows PRESENT status, the problem needs to be fixed before the code can be cleared. If your BMW has no sound or power, there will typically be a fault code stored in the MOST module.

List of scanners that read and clear BMW MOST fault codes.

These are only a few examples. Many diagnostic scanners allow you to read and clear BMW MOST fault codes. To learn about OBD2 scanners that work on BMWs, check the article on Choosing the best OBD2 scanner for BMW.


  1. Plugin the OBD-II scanner into the diagnostic port under the dashboard.diagnose bmw MOST fault code via obd2 port
  2. Turn on the ignition; don't start the engine.turn on bmw ignition to read MOST fault codes
  3. Turn on the scanner and select your BMW chassis. Next, Select the Control Units MOST control unit module reading codes
  4. Select the MOST Module.
  5. Once you enter the MOST module, you will be able to do the following.
    • Read Codes from MOST Module
    • Clear Codes from MOST Module
    • Perform Adaptations, Activations, Tests

BYPASS using Fiber Optic Loop

You can also diagnose BMW radio problems using a Fiber Optic Loop.

bmw fiber optic loopThe MOST BUS signal (red light that flashes in the fiber optic cable) generates from the head unit, which will be your NBT, CIC, or CCC unit.

The signal passed through each module one at a time, including an amplifier, ask unit, amplifiers, tuner, Bluetooth phone, etc.

To find out which unit is the culprit, you can use a female fiber optic loop to bypass each component one at a time.

When you bypass the defective module, the sound should be back. Most of the BMW audio modules are located on the left side of the trunk.

If the defective component is critical, you will need to replace the module or get it repaired. Unless the defective module is not critical, such as a CD changer, you can live without it.

How to find a defective module

  1. Locate the MOST components on the left side of the trunk. You will be unplugging the fiber optic cable from one unit at a time and install a female bypass loop. Start by passing the telephone unit.
  2. Turn on the radio and check if the radio is working and if you have sound.
  3. If the first module you bypassed didn't fix the problem, reinstall the fiber optic cable and go to the next module. Disconnect each of the modules one at a time and install the bypass loop. When the head unit (radio) starts working, you have identified the failed unit.

Replacing BMW audio units can be very expensive because they need to be programmed as well. A cheaper alternative is to repair your unit.

Many services will fix your defective unit for a fraction of the dealer price.

BMW Audio Control Unit Repair Services

Frequently Asked Questions

Can I install an aftermarket on the BMW car?

  • Use a BMW MOST Fiber Optic Amp Interface. It is possible to keep the factory speakers, amplifier, and even subwoofer working with an aftermarket radio.

In which cars can I used a MOST fiber optic interface?

  • You can install an aftermarket radio on any BMW. Some examples include E90, E91, E92, E93, E60, E61, E81, E82, E83, E84, E70, E87, E88, E89
okc's Avatar

Drives: e90

Join Date: Feb

Location: okc

QuestionHelp with speakers not working

my speakers has been bugging me for a little while, something didn't sound right *sometimes*. i finally figured out my driver's side speakers aren't working. i have logic 7 fwiw. when i turn the balance all the way to the left and turn fader all the way to the front, i don't hear music (very very faint).

this morning, while i was doing this, i decided to turn up the volume, and suddenly the front left speakers work again! i turn the volume down and restore the balance and fader and everything works.

i know it will stop working again just don't know when, because it had done this in the past.

my question is, what the hell happened? is it possible for speakers to be "stuck" until i give it a higher amp ? or could it be the amp that's going out?
Please help!

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Jez_zza's Avatar

Drives: M5 F90

Join Date: Jan

Location: Barcelona

No sound coming out of the speakers .. help !

I just came back from my local shop where I had the car wrapped.
They kept the car for 4 days, when I picked it up had to reset the time but did not think much of it.
When driving back noticed that I had no sound at all coming from the speakers.. no music (iPhone, radio), no sat nav , no voice control , no parking sensor tune , just nothing. I called the shop to see if they had done something to the car , unplugged a cable or a fuse and the answer was just a straight no
So would anyone there could tell me what is wrong ? and I could get this fixed ? thanks !

Last edited by Jez_zza; at PM..

BMW no audio fixed!
ItsGary's Avatar

Drives: E90 M3
Originally Posted by l2icemanView Post
bump - anyone have an answer for this? I have the Individual Audio, and my driver side speaker/tweeter are not working. I took a look at the fuse box diagram, looks like fuses related to the sound system are 14, 15, 18, 19, 27, 42, 56,

I noticed fuses 14 and 15 were missing completely - I installed new ones, but didn't make a difference.

Anyone have a diagram on what the fuses specifically link to? Wondering if it's normal for fuse 14/15 to be missing (ie not used for those with Individual Audio?)
My speakers stopped working because I had water in the trunk. It blew the Driver side door speaker.
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'09 ///M3 Sedan - Jerez Black/Fox Red Ext.
'09 i Coupe - Alpine White/Black - SOLD

Speakers not working bmw

Why Did My Car Speakers Stop Working?

Car speakers tend to wear out, and even break, over time. This is especially true with the kind of lower quality original equipment (OE) speakers that most cars and trucks come equipped with. Internal components can wear out or come loose through regular use, and there's not a lot that can be done about it.

That being said, car speakers tend to fail one at a time. Every speaker in a car audio system dying at once is very unlikely without some serious abuse, like cranking the volume high enough to blow the speakers out. When all of the speakers in a car audio system all stop working at once, the problem is usually in the head unit,  in the amp, or in the wiring.

In some cases, an issue with the wiring between the head unit and a single speaker can even cause all of the speakers in an entire car audio system to cut out at once.

In order to narrow down the exact cause of this type of car audio problem, some basic troubleshooting is in order.

Ruling Out the Head Unit and Amplifier

If your head unit turns on just fine, but you don’t get any sound from the speakers, it’s easy to jump to the conclusion that the speakers are the problem. However, the fact that the head unit is turning on doesn’t mean it’s working properly. Before you do anything else, you’ll want to:

  1. Verify that the head unit hasn’t entered an anti-theft mode that requires a car radio code.

  2. Check the volume, fade and pan settings.

  3. Test different audio inputs (i.e. radio, CD player, auxiliary input, etc).

  4. Test any onboard fuses.

  5. Check for loose or unplugged wires.

If you are unable to locate any issues with the head unit, then you will want to determine whether or not you have an external amplifier. In-car audio systems that use external amps (both OEM and aftermarket), the amp is the most common cause of this type of problem, since the audio has to pass through it on the way to the speakers. In the process of checking out the amp, you will want to:

  1. Verify that the amplifier is actually turning on.

  2. Determine whether or not the amp has gone into “protect mode.”

  3. Inspect for loose or disconnected input or output speaker wires.

  4. Test both inline and onboard fuses.

Although there are many common car amplifier problems that you can identify and fix on your own, you may run into a situation where the amp seems fine even though it has failed. In that case, you may need to simply bypass the amplifier to verify that both the head unit and speakers are working, at which point you can either get by with your head unit’s internal amp or install a new aftermarket amp.

Checking Car Speaker Wiring

When you checked the fade and pan settings on your head unit, you may have discovered that they were set to a speaker or speakers that had failed and that you were able to get sound by moving to a speaker or speakers that work. In that case, you’re looking at a problem with your car stereo wiring or a faulty speaker or speakers.

Since speaker wires are often routed behind panels and molding, under seats, and beneath the carpet, it can be difficult to visibly inspect them. Depending on your situation, it may be easier to check for continuity between one end of each wire (at the head unit or amp) and the other end at each speaker. If you don’t see continuity, that means the wire is broken somewhere. On the other hand, if you see continuity to ground, then you’re dealing with a shorted wire.

If your speakers are mounted in doors, then a common point of failure is where the speaker wire passes between the door and the door frame. Although door wiring harnesses are typically protected by hard rubber sheathes, the wires can still end up breaking over time due to the repeated stresses endured in opening and closing the doors. With that in mind, you may also want to check for continuity and shorts with the doors both open and closes. If you find that one speaker is shorted to ground in that manner, that can actually cause all of the speakers to cut out.

Testing Car Speakers

Another way to test the speakers, and to rule out bad wiring at the same time, is to obtain some speaker wire and to simply run new, temporary wires to each speaker. Since this is only temporary, you will have to gain access to the speakers by removing door panels, trim, and other components, but you won’t actually have to route the new wires properly.

If the speakers work with the new wires, it’s a safe bet that your problem is with the old wiring, in which case routing new wires will fix the problem.

You can also “test” car speakers by unplugging the wiring harness from the head unit or amp and touching the positive and negative wires of each speaker, in turn, to the positive and negative terminals of a V battery.

If the speaker wires aren’t broken, and the speaker hasn’t totally failed, you will hear a slight pop when you touch the wires to the battery terminals. However, the fact that you can get a “pop” out of a speaker with a V battery doesn’t necessarily mean the speaker is in good working order.

If you end up ruling everything else out, and you really are dealing with a coincidental failure, then it's time to just replace your car speakers en masse. However, you should probably make sure that they weren't blown out by someone cranking up the stereo.

This may also be a good time to think about upgrading your car stereo as a whole, although selecting some good aftermarket speakers to replace the blown factory units can actually help a lot by itself.

How Can You Tell If Car Speakers Are Blown Out?

It's pretty easy to tell when car speakers blow out if you're there when it happens because you'll immediately notice that they stop working or no longer sound normal. If it happens when you're not around, and the guilty party isn't willing to fess up, verifying blown speakers takes a little work.

The surest way to test whether car speakers are blown out is to disconnect the speaker and check for continuity. If there isn't any continuity between the speaker terminals, that usually means it's blown.

Thanks for letting us know!

BMW NO Audio/Radio FIX! A Very Simple $10 Part


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