I've recently bought this kind of device for my "Citroen C4 Coupe" with the RD4 - N1 radio (Label: Blaupunkt):


Then I realised, that the radio doesn't come with a standard aux-in. So I decided to install it myself. After informing myself a little bit, I bought those two components:

AUX-IN ADAPTER CITROEN & PEUGEOT (from Amazon) AUDIO ADAPTER, 3,5mm (from Amazon)

After plugging in the Aux-In Adapter hopefully correct, I realised that nothing happened. So after searching for a while, I read in some forums, that the citroen c4 car dealer has to unlock the aux-input. Today I was at a nearby dealer and he told me, it would cost up to 50 or 60 Euro. That's basically to much I guess! ????

Now my question:

Is there a better way to do this?

A friend of mine is a ford car mechanics, he could give me a can-bus for my car. Maybe he also could give me the laptop, but more interesting:


(or How is it named? I can do the rest.)

Any suggestions?

Greetings from germany

  • Hans! I have the same problem. Did you solve yours?
    – user10942
    Commented Jun 19, 2015 at 22:39

2 Answers 2


The correct maintenance software is called Lexia, and is regularly available for authorized service stations only. Lexia is more commonly distributed as part of a larger software package called DiagBox. Both are suitable for unlocking the AUX-port.

You also need the Lexia ODB2 Diagnostic Cable assembly, which is usually comprised of three different cables: the ODB2 to 30-pin converter (with an LED in the plug), the 30-pin to 16-pin converter, and the 16-pin to USB-converter.


Go on ebay or amazon and look for "citoren lexia" You'll get plenty results with the cables you will need to unlock (as stated in the answer before) And quite possibly you'll also get a CD with software provided. I'd rather not speculate if the software that they might provide is lexia or not, as (as far as i know) obtaining a legal copy of it might be quite pricey. What you can do is shop around for a service center (preferably smaller ones) that might have the cables (and the software they need) to help you out for a bit less, at it shouldn't take no more than 15 minutes.

This being said, I too tried to get AUX on the same radio in my Citroen. I tried all possible combinations on both ports on the back of the radio (there are 1 or decent instructions sets online) but failed and too came to the horrible realization that i need the cables (and the software). But it might be worth the investment as you can do quite ALOT with the set, and even if not, you can later resell them for nearly as much as you payed for them.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .