Checklist for replacing Head Unit.

I’ve just bought my first A2 2004 and considering reverting from a Kenwood HU (currently in there when I bought it) back to a OEM HU with aux/Bluetooth if this is possible... I have Bose, so what HU should I be looking for please?
 

audifan

A2OC Donor
Firstly is the dash single or double DIN? After that then the Generation 2 stereos are your best bet. Also depending on what has been butchered you may need to reinstate other components and wiring loom. You are doing the right thing by reverting OEM especially since you have Bose.
 
Firstly is the dash single or double DIN? After that then the Generation 2 stereos are your best bet. Also depending on what has been butchered you may need to reinstate other components and wiring loom. You are doing the right thing by reverting OEM especially since you have Bose.

Hi Audifan

Single DIN in there currently. Hate to think what’s been hacked behind it, but will find out soon enough 😂

I’m a newbie, so what are the second gen stereos? Do they have Bluetooth or aux? Just want to plug my phone in for Spotify

Cheers
 

Erlingtheelder

A2OC Donor
Hi Audifan

Single DIN in there currently. Hate to think what’s been hacked behind it, but will find out soon enough 😂

I’m a newbie, so what are the second gen stereos? Do they have Bluetooth or aux? Just want to plug my phone in for Spotify

Cheers
You’ll need an x car link or something similar for all OEM headsets. Simple enough to fit though.
 

audifan

A2OC Donor
Nothing fitted by Audi to the A2 had bluetooth or aux inputs. Easy enough fit one of the adapters out there ( 3 brands that I can think of ) into the cd input on the rear of the Audi units. Generation 2 stereo in single din is the Concert 2 which has a single cd slot. correction 4 companies including this example...



And this is what a Concert 2 looks like and can be coded for Bose....

1607467238984.png


Important to get one for the A2 as the other models this unit was also fitted into have a larger bezel.
 
Nothing fitted by Audi to the A2 had bluetooth or aux inputs. Easy enough fit one of the adapters out there ( 3 brands that I can think of ) into the cd input on the rear of the Audi units. Generation 2 stereo in single din is the Concert 2 which has a single cd slot. correction 4 companies including this example...



And this is what a Concert 2 looks like and can be coded for Bose....

View attachment 73919

Important to get one for the A2 as the other models this unit was also fitted into have a larger bezel.

Ace, thanks for passing on your knowledge. I’m assuming eBay is the best place for the Concert 2?
 

audifan

A2OC Donor
Important to find out how much butchery has been done to the wiring, then you may be able to source a Concert and enough of the original wiring to repair whatever you find from one of the recyclers on here. As far as the adapter may get one one here but more likely ebay or similar.

As you are new and probably not aware, if you click on your user name then Account upgrades and pay the one off £2 fee you can then access Market where you can browse for items for sale or even place wanted adverts.
 
Important to find out how much butchery has been done to the wiring, then you may be able to source a Concert and enough of the original wiring to repair whatever you find from one of the recyclers on here. As far as the adapter may get one one here but more likely ebay or similar.

As you are new and probably not aware, if you click on your user name then Account upgrades and pay the one off £2 fee you can then access Market where you can browse for items for sale or even place wanted adverts.

Ah that’s £2 worth spending, appreciate your help 👍

One final question, for now, what’s the difference does the Bose make to the HU? Is it a different version, or the wiring?
 

audifan

A2OC Donor
No real difference to the head unit just enables the Bose system. Look identical in the dash and hopefully all your wiring still exists.
The word BOSE appears on the display and this lives in the boot....


1607468238788.png


It may look different for 2 main reasons. One the disc mounted cd changer that you can see is mounted in a different boot side panel and the black piece over the battery with the triangular cut out is a spare wheel carrying bracket again was optional. Both unlikely to be fitted to your car. But can be upgraded to have these items.

The other difference with Bose cars is that the tool kit that is normally located in the boot is relocated to under the drivers floor.
 

Proghound

Admin Team
One final question, for now, what’s the difference does the Bose make to the HU? Is it a different version, or the wiring?
Bose is a separate amplifier under the driver's footwell, which uses the unamplified line-out from the HU to power special speakers and a subwoofer in the boot, all of which are tuned to deliver the best sound response for the interior shape of the A2. The OEM HU needs to be coded for Bose to make the output to the amp just the flat EQ (if that's the correct term).

I hope you still have the genuine Bose speakers in the doors. It would be worth you having the doorcards off to check both the woofers (BOSE marking on the labels) and tweeters (same, plus their labels are orange). Likewise check in the battery compartment below the boot floor that the sub is in place. Lastly lift the driver's carpet, turn the three plastic tags through 90degrees and lift the aluminium panel, your tyre-changing tools should be in a foam holder in there, lift that out and the black BOSE amp should be underneath.
 

Kleynie

Member
Surely the easiest way to check if Bose has been messed with is to remove the existing head unit and check if the speaker outputs are used, if they are not and the ‘line out’ RCA connections are used then Bose IS being fed in the correct way = no blown speakers and no need to remove door cards.

Ian
 

audifan

A2OC Donor
That is part of the issue, new owner and little knowledge of how the head unit swap was carried out Ian. Does the aftermarket have RCA? Was it adapted by chopping off the RCA plugs. We do not know, just advising what may be in store, what to look for and where. All we really know including the new owner is that the car came Bose equipped and that the aftermarket non Audi head unit currently fitted wants to be swapped back to Audi OEM with additional bluetooth and aux support.
 
That is part of the issue, new owner and little knowledge of how the head unit swap was carried out Ian. Does the aftermarket have RCA? Was it adapted by chopping off the RCA plugs. We do not know, just advising what may be in store, what to look for and where. All we really know including the new owner is that the car came Bose equipped and that the aftermarket non Audi head unit currently fitted wants to be swapped back to Audi OEM with additional bluetooth and aux support.

I’ll send you a picture of the boot later this morning. I’m sure there is definitely Bose in the boot, but will check under the driver seat as well.
 

PlasticMac

Member
Ah that’s £2 worth spending, appreciate your help 👍

One final question, for now, what’s the difference does the Bose make to the HU? Is it a different version, or the wiring?
Bose and non Bose HUs are the same physically. The difference is in setup. So, you can buy a non Bose Concert or Chorus, and code it for Bose (or vice versa) with VCDS. Bose HUs are often priced higher than non Bose, so, don't get caught!

Max.
 
Bose and non Bose HUs are the same physically. The difference is in setup. So, you can buy a non Bose Concert or Chorus, and code it for Bose (or vice versa) with VCDS. Bose HUs are often priced higher than non Bose, so, don't get caught!

Max.

Ah great shout, thanks. How do you code it, does this require any specialist kit?

Thanks for all the help guys, really appreciate the time you’re taking to help a newbie 👍🙏😉
 
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