I have been a little paranoid to take my stereo out of the car due to a few people on the forums. They said that the radio once disconnected from the battery would ask for a key code (Anti theft device). After gaining a bit of courage, and realizing what I had to loose (After I blew the cd changer up, I only could listen to One radio station to the band expander not working..) I disconnected the stereo!
There is no anti-theft code of any sort on the AU-650 found in the 1997 Audi A4 Quattro! (Although you cant blame me if yours asks for one lol)
A few pics and a wiring diagram:
Pin-out for the AU-650
Front
Back
Connections
Aerial Plug Location (*dashboard :P)
Will's Audi A4 Quattro B5 Worklog 
Hi there, very interesting stuff. I’m a bit like you scared to unplug the radio as I don’t have the security codes if it needs them. I want to fit a band expander and figure I need to pick-up power (for the band expander) from pin 5 on the ‘C’ connector. What do you think? Also, which is the aerial connection and what sort of plug does it use (I can’t quite see from your photos). Thanks
By: Johnhh on February 12, 2011
at 2:46 am
Hi John!
Thanks for the response,
As for the radio, if yours is the same as mine (AU-650) then from what I experienced, it does not have any security codes. So you’ll be safe if you pull it out to have a look behind.
Ive not played much with band expanders before, didn’t even realise they needed power. As far as pin 5 goes, I wouldnt cut it off fully, just tap into it with your band expander. There could be something that need the ANT REM OUT somewhere along the antenna…?
Have a look at the new image I added to this post, hopefully this will give you a better idea of the aerial connector plug thing. Shots were taken in the dark on my iphone, so sorry for bad quality!
Will,
By: willtblog on February 12, 2011
at 9:24 pm
Hi Will,
Thanks for your help and for posting the extra photo – very useful.
I’m just about ready to tackle the job but first will have to get hold of a couple of the removal tools. I’ll see if the Audi dealership can help.
My radio (on the cassette door) shows AU-660 as the model number but I’m guessing it’s the same as yours – looks identical to your photo. Soon tell once I get it out. I’ll let you know how I get on.
Keep up the excellent blog – I’m slowly working my way through it and find it very informative.
Thanks once again
Johnhh
By: Johnhh on February 13, 2011
at 10:19 am
No problem Johnhh, Glad that this blog helped!
To save you the trouble of getting hold of the radio removal keys, have a go at making them yourself – thats what I did. https://audicarpc.wordpress.com/2010/04/06/mod-2-diy-radio-removal-key/
By: willtblog on February 13, 2011
at 2:23 pm
Thanks for the tips Will. After reading your article I found a couple of old radio removal tools and did a quick modification to turn them into Audi ones. Worked perfectly. Thanks again. Johnhh
PS. I’ve taken a couple of pix of the tools but can’t post them on your blog. Any ideas?
By: Johnhh on February 15, 2011
at 12:04 pm
Sweet!
Upload them to http://tinypic.com/ and Ill have a look!
By: willtblog on February 15, 2011
at 12:15 pm
http://tinypic.com/r/2dke7ow/7
http://tinypic.com/r/k04xw8/7
I didn’t create an account on tinypic so hope you can see them using the above links…..
By: Johnhh on February 15, 2011
at 1:23 pm
Thats great, I bet they work way better than mine.. Mine bend really easily!
Ill add them to https://audicarpc.wordpress.com/2010/04/06/mod-2-diy-radio-removal-key/ if you dont mind?
By: willtblog on February 15, 2011
at 2:18 pm
By all means please add them – I would have copied your design just I didn’t have any beer handy…..
My next question is, ‘now I have the radio out am I brave enough to unplug it’?
By: Johnhh on February 16, 2011
at 11:48 am