[BMWtony]

I installed an aftermarket HU about 3 months ago with can bus integration all plug and play and everything works good, steering wheel controls, it shows which doors are open, mpg,ect... No codes. But yesterday a message popped up twice "check gas cap" than the check engine light came on. So I took it to the dealer the tech cleared the check engine light (code P0442 minor evap leak. A glitch he said. I did tighten the cap.) He wanted to reprogram/update software in the vehicle but was unable to: “Due to aftermarket audio equip. interfering with MOST bus communication.” So my question is can both OEM HU and aftermarket HU share the same can bus If I install the OEM HU in the trunk? (MOST cables to OEM HU in trunk of course) The reason I am asking is tech said he could not get passed the aftermarket HU. The program could not identify the components like the bluetooth, Nav.,DVD in the aftermarket HU. It told him to replace HU first.

Basic Professional HU/CD player and USB and AUX ports in center console
any help or advice?

[ctuna]

Unless there machine see's the original setup, it can't go any further.
This is a common problem with aftermarket head units .
To avoid this problem people do a parallel mount or run wires
for a parallel mount and plug the head unit in when they need an
upgrade or repair from BMW.
All those units he was talking about are connected via the most bus through the radio . No radio no most bus no communication.
A coding setup can update individual modules without
the radio but BMW doesn't support that and there machine offers them no way to bypass its rigid test sequence.

Look at the second link for info on setting up a parallel
mount.

head unit
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.janus-design.net/english/
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...light=retrofit
http://www.e90post.com/forums/showth...hlight=dynavin

You probably don't need any updates anyway but you
might need a repair from them in the future.

[BMWtony]

Originally Posted by ctuna

Unless there machine see's the original setup, it can't go any further.
This is a common problem with aftermarket head units .
To avoid this problem people do a parallel mount or run wires
for a parallel mount and plug the head unit in when they need an
upgrade or repair from BMW.
All those units he was talking about are connected via the most bus through the radio . No radio no most bus no communication.
A coding setup can update individual modules without
the radio but BMW doesn't support that and there machine offers them no way to bypass its rigid test sequence.

Look at the second link for info on setting up a parallel
mount.

head unit
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.janus-design.net/english/
http://www.e90post.com/forums/showth...ight=head+unit
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...hlight=dynavin
http://www.e90post.com/forums/showth...light=retrofit
http://www.e90post.com/forums/showth...hlight=dynavin

You probably don't need any updates anyway but you
might need a repair from them in the future.

thanks for your replay ctuna

After checking that second post I was still unsure of connecting both HU's to the same can bus at the same time. I was concerned that the aftermarket HU might cause some kind of interference. I will only plug the head unit in when they need an upgrade or repair from BMW. Maybe Turning off the aftermarket HU when ever I take it in will help so that they are not on at the same time. Does the OEM HU need to be powered on while in the trunk?

Thanks you
Now I need to get all the stuff together

female HU harness
Fiber optic cables
Fiber optic splicers/connectors
14 gauge wire
quick connects

[BMWtony]

If I install the loop jumper part#61136917541 will it work for the software updates or do I need the can bus +- hooked up to the OEM HU anyway?

[ctuna]

I think you need the can bus connection.
The can bus is the way the radio communicates
with the rest of the car its the gateway to the most
bus through the radio.
I have don't have and aftermarket head unit but
there are people here that have direct experience with
this like BMW325i I would consult with him on the details.

BMW stereo types

Read the entertainment system pdf

http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...4&d=1278871872

[bmw325i]

The head unit needs to be connected to the most access port in the lower dash. You also need power ground and can wires connected. You probably already have unused most cables in the trunk you just have to switch them around in the most distribution block behind the drivers side rear seat bolster and you can use a most termination loop in the dash. It makes no difference that you have an aftermarket head unit installed. The problem is you don't have the stock head unit installed.

[BMWtony]

Originally Posted by bmw325i

The head unit needs to be connected to the most access port in the lower dash. You also need power ground and can wires connected. You probably already have unused most cables in the trunk you just have to switch them around in the most distribution block behind the drivers side rear seat bolster and you can use a most termination loop in the dash. It makes no difference that you have an aftermarket head unit installed. The problem is you don't have the stock head unit installed.

I will look for extra most cables in the trunk area and run the wires required for the HU.
I was hoping I could just have a female HU harness/can bus connection in the glove box where i could hook up the HU when I went in for repairs and stuff.
That would be to easy.

Ok thanks for your help

I now have a better understanding of what I need to do

[bmw325i]

Originally Posted by BMWtony

I will look for extra most cables in the trunk area and run the wires required for the HU.
I was hoping I could just have a female HU harness/can bus connection in the glove box where i could hook up the HU when I went in for repairs and stuff.
That would be to easy.

Ok thanks for your help

I now have a better understanding of what I need to do

That can also work. You just need to extend the fiber optic cables to the glovebox along with power, ground, and the 2 can wires.

[BMWtony]

Originally Posted by bmw325i

That can also work. You just need to extend the fiber optic cables to the glovebox along with power, ground, and the 2 can wires.

Ya, that is much better I was stressing out just thinking about tear up everything all the way back to the trunk.

That will save me $$ and a lot of time. Now if I can cut the store bought fiber optic cable and make 2-3ft cables. I think I read somewhere it needs a straight 90 degree cut.

Thanks again
I'm sure glad you all are around

[e90bmw328i]

Originally Posted by BMWtony

Ya, that is much better I was stressing out just thinking about tear up everything all the way back to the trunk.

That will save me $$ and a lot of time. Now if I can cut the store bought fiber optic cable and make 2-3ft cables. I think I read somewhere it needs a straight 90 degree cut.

Thanks again
I'm sure glad you all are around

I don't think the glove box is big enough to fit the stock head unit. Although you can have connector there and plug in the radio when u go for service. I am planning to do the same.

[BMWtony]

Originally Posted by Metblack328i

I don't think the glove box is big enough to fit the stock head unit. Although you can have connector there and plug in the radio when u go for service. I am planning to do the same.

the pin contacts #6113601846 and 47 were hard to find (Discontinued) even the dealership replaces the part number with 61136905233 and 61136906554

finally found them on getBMWparts.com
The thing is you dont get a picture of what your buying you type in the part No. and and add it to your cart

good luck with with your project

[BMWtony]

Originally Posted by bmw325i

That can also work. You just need to extend the fiber optic cables to the glovebox along with power, ground, and the 2 can wires.

I am in the middle of moving OEM radio install and have ran the required wires and fiber optics to new location.
I have a question about the 12v+(constant) to the head unit. I have connected the 12v+ to pin 15 on head unit. Does the acc 12v+(pin 16) need to be hooked up too? Does the radio have to be on (with the key on) when they need to update software?

Update: After looking at the car radio harness there is no wire in pin 16 Acc+12v so I guess it does not need it. The OEM radio turns on when I push the power button on HU unit. It is all complete now so whenever I need to have the OEM unit I will just plug it in.

by the way I have the Plug under front passenger seat instead of the glove box the radio fits a little better under there.

Thanks to everybody for your help