I tried to install my Pioneer 3500 MP3 head unit into my octy just now.

The head unit comes with an ISO lead which plugs straight into the octy's iso socket.

I plugged it in an it worked perfectly, great! I thought. So I went to get the din cage, fitted that, then plugged the head unit back in....smoke plumes out of the back of the unit!?! I unplug the lead. Check the other leads, plug it back in...no smoke?

So I swtch the acc on, major smoke, odd sounds from the speakers, dead head unit!

WTF!?!?!?!

Oh dear sounds a real problem

VAG Group cars do not have standard ISO pin layouts. One important difference is that permanent live and switched live are reversed from the ISO standard. However that only normally means that you loose the presets and have to put in the security code each time you start up. It is not normally terminal - it certainly does not release the magic smoke.

It is very tight behind the unit and fitting can crush and damage leads, leading to short circuits and blown fuses. Suggest you first check fuses as that may the simple (and cheap to fix) reason why your hu isn't working. After that is down to checking all the wires to look for damage.

do a search on k line IIRC, you need an adaptor or an aftermarket headunit will do all sorts of damage.....

I really hope it's only a wire or two on the h/u loom. Though fixing it may be a real PITA. Get chatty with your local ICE installers as they may be able to fix it for peanuts (

another thing to be aware of apart from swapping the power supplies round as previously mentioned is that if you plug directly onto the factory iso connectors you will see that the pin for electric aerial output on the radio side of the plug(usually blue)connects to a permanant 12v supply in the skoda side of the plug(usually a thick red/white wire) which can sometimes cause problems with certain head units or even drain the battery by sending a back feed into the stereo via the electric aerial output wire so its worth disconnecting this wire which is usually blue on most stereos plus if your fitting the aerial booster then you can connect the wire off the booster directly to the blue from the head unit where you have chopped it and as for the k-line wire then its usually safe as most stereos don`t have a wire in that position of the plug but be careful if your plugging the iso`s directly into the stereo like on jvc`s cos they can cause a short on the k-line

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So what you're saying is that what looks like a std ISO connector in the Octy is in fact NOT a std ISO connector!!!

The lead that came with the h/u terminates in an ISO socket, I just plugged the octy plugs into that.

either you have trapped a wire and fried the unit or its faulty. i plugged my stereo straight in and it worked perfectly.

I believe that there have been problems with non-OEM HUs knackering some diagnostic equipment because, if not connected properly with the appropriate adaptor, there is 12V on the K line which shouldn't be there.

Ross-Tech have an explanation of that problem below:

http://www.ross-tech.com/vag-com/aftermarket-radio.html

Some HU's might be ok because they might not have all the ISO pins connected so don't screw with the k line etc but best to get a pinout diagram and disconnect any core that are not used or not compatible with the HU.

However, i've burnt out a couple and repaired a load of car stereos in my time and smoke is bad. If the speaker wires had been connected to 12v or something then it wouldn't be a big deal to get the power amp in the HU replaced. Bit awkward but no big deal. however it's nore likely that you've fried something on the main board which is probably covered in surface mount components. May be unrepairable. Prepare to drop it in the bin.

So what you're saying is that what looks like a std ISO connector in the Octy is in fact NOT a std ISO connector!!!

The lead that came with the h/u terminates in an ISO socket' date=' I just plugged the octy plugs into that.[/quote']

Yep

As I understand it the term "standard" as used in standard ISO may be not be quite accurate, certainly for VAG cars. Thats why it is best to try to get audio pin out and car wiring diagrams