Amp coding is a processes that must be done by a dealer or someone who has BMW's proprietary diagnostics computer system. Essentially, they connect their system to your car, and it configures all of the components attached to the car to work together.

For your second question, the amp will shut off after about 30 seconds if it is not coded properly for your car. So, you will only be able to get an effective test of audio for the first 30 seconds.

If you are seeing the DSP option on the nav screen, you have the basics connected properly. It only takes power, ground, and the "I-Bus" wire to get the DSP to show. That means that the amp is powered up and communicating with the nav computer. That is very good.

However, if you are not hearing any audio, then the radio outputs may not be connected to the amp, or the speaker wires may not be connected. I doubt that you have misconnected every speaker wire, so I suspect that it is your radio outputs that are the problem. I would double-check the wiring between the radio and the DSP amp.

Also, do you have the round pin radio or the flat pin radio? If you have the round pin radio, then try the CD changer. The CD changer feeds its audio directly to the DSP amp through that little coax cable. It bypasses the radio entirely, so it would be a good test to isolate the DSP amp.

If you have a flat pin radio, then the above test won't work. The CD audio feeds through the radio with the new gen flat pin radios. However, if you have a flat pin radio, make sure that you have a Loewe or Lear DSP amp. The Philips amps are not compatible with the flat pin radios.

Brian, thank you for your speedy response!

I am seeing the DSP option on the nav screen and it's not shutting off after 30 seconds so i know that at least some if it is hooked up properly. Regarding the outputs from the head unit to the amp, do you know which ones carry the sound output i should check? would that go into the larger 15-pin plug on the amp or the smaller 18-pin (i think) plug?
Strangely, though, the "Room/Echo" and "Set" options of the DSP menu are greyed out. Not always though, sometimes they are available and i can't figure out why that is.

Also, is there a relay that could be limiting the sound from the speakers?

Lastly, the previous owner replaced the factory CD changer with a alpine CD changer with a blitzsafe converting the connection. I'm not sure why he did this. So... although i have a round plug on the amp that should go to the CD changer ( i guess), it's not going anywhere right now.

Once again, thank you for your help!

Here's a post that shows the wiring coming out of the radio.

http://www.xoutpost.com/articles/x5/s...formation.html

Thanks a lot, Brian!

I bought a 65.12-6 905 119 amp from eBay to replace the defective one in my car, but the tag was not on the amp when I received it. Is there anyway to verify the part number is correct? Thank you! :thumbup:

if it is a DSP ampo, the part number is stored inside the unit in an EEPROM

You can read the part number with diagnostic software or with my NavCoder software

Where can I read up on the Navcoder? I did some googling and it seems really useful, but I cannot find much on how to use it, etc. Thanks!