E46 Business CD No Sound!

[JeffLebowski]

Hey everyone, first post here. I have a 2003.5 M3, and it would seem that something in my Business CD non-HK system has bit the dust. I can't seem to track down what it is, since all of the sudden the sound system just stopped producing any sound at all.

All of the functions work, just no sound on anything. Where are the fuse locations for the factory amp, or what other things should I check out before I pull this whole factory head-unit out for replacement?

[Halston Pitman]

To confirm no sources have audio? AM/FM/CD? Changer?

[JeffLebowski]

Correct, no sources have any audio at all, and fuses #7 and #41 appear to be fine. No cracking or popping from speakers, just silence.

[yellowboss]

Did you find the source of this problem? I have exact same thing happening on 2003 e46. The battery died, I replaced it, then all of a sudden no sound on any speakers whether it is FM, AM, CD, silence.

Appreciate any info on how you solved this.

[foggy1]

Wondering if you figured out what the problem was? I see a lot of post with the 'Power but no sound problem" however no real concrete solutions. Please post if you figure it out. I was told that in 95% of these cases the issue is with the amp but it's the other 5% that worries me.

[foggy1]

I replaced my amp with the exact same amp that I bought second hand from e-bay, Identical part # as the original amp I had in the car. That was what cured my problem. The amp I had was no good. I'm not 100% positive, however I beleive that you need to swap your amp with the identical amp (same part #) as the one you have in your car now and not just any BMW amp or aftermarket. Should be able to find them on e-bay.

[BrknArrw]

Hello,

I thought I'd add to this thread, my daughter recently bought a 2007 BMW X3 with the same problem described in this thread; E46 Business CD radio visually functions correctly but no sound. Found a replacement amp on ebay for $200. Decided to do a little additional troubleshooting before spending the $200. I searched the internet for wiring diagrams for this vehicle with little success. I was able to find a pinout for the radio side of the plug. I then disconnected the amp side and used a multimeter to determine the pinout on the amp side.

This is what I came up with:

Head Side Amp Side
RF+ 2 ------------------------- 9
LF+ 3 ------------------------- 38
RF- 6 ------------------------- 17
LF- 7 ------------------------- 30

Can-Low 9 --------------------- 26
Rem Mute 10 -------------------- 28
Can-High 11 --------------------- -
GND 12 --------------------- 26

Rad_On 13 --------------------- 10
KL58G Blght 14 ------------------ -
KL30 Bat. 15 --------------------- 5
Gateway 16 --------------------- -



This allowed me to attach some old Cambridge Soundworks PC speakers to the amp side plug and verify that the radio works and that the amp was defective.

We bought the replacement amp and that solved the problem.