pcm, no sound, navigation not available, telephone not available, maps not available, cd changer not available

[224STU]

Sent my head unit to maple,, a mates offered to let me try his head unit in my car out of curiosity,, would it plug and play or are they coded to the car ?? Thanks


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[Richard Hamilton]

It should be coded to the car, unless the security coding has been removed by a specialist.

[224STU]

Ok thanks... waste of time trying then


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[224STU]

All sorted.. faulty head unit.. thanks for your held !!


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[Loren]

7 hours ago, 224STU said:

All sorted.. faulty head unit.. thanks for your held !!


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[Sparkatan]

Hi, I have just purchased a 996 C4 2004 and the pcm2 indicates the above message. When I try to operate the radio I can find a programme but there is no sound. There is a cd changer under the front bonnet but it does not appear to have power to it, or I am concluding that as the disc tray doesn’t eject when I press the button.

I understand a pcm2 manual can be downloaded from this site but where is it?

[Richard Hamilton]

If the CD Changer isn't getting power, it will cause a break in the fibre optic loop, and there will be no sound and no phone.  First check fuses D8, D9, D10, E5 and E8 on the panel in the driver;s footwell.  If that doesn't help, check you are getting 12v to the power plug on the CDC witha multimeter or test bulb.  If you get 12v there, it may be that the glass fuse on the circuit board of the CDC has blown.  It is replaceable, but you have to take the CDC out and take off the covers to access it.

[Sparkatan]

Richard, thanks for the reply.

Since posting I had a look at the cd auto changer and found the power plug and what I believe is a fibre optic cable to have been left loose. The fibre optic cable appears to have some sort of bridge fitted to it. Also, in the glove box is a device with a usb plug and an older type iPod plug on a cable connected to it. The device also has a couple of audio plugs and a blue light. 

I plugged my iPhone into the usb and nothing happened apart from the iPhone showing a charging sign which pulsed on and off. When I plugged the connector into my iPod it said Dension on the iPod but nothing changed on the car audio.

Any ideas what this is all about?

[Richard Hamilton]

The Dension is a device for connecting an iPod to the fibre optic loop.  It emulates the CDC, so that's why it has been bridged out of the loop.  There should be two orange optical cables running to the Dension, usually in a black plug.  Is it connected?

[Sparkatan]

Is the Dension that little junction box with the usb and audio plugs on it? If so it is screwed to the roof of the glove box. The cable could enter from behind but I can’t see it. I’ll have a look tomorrow.

[Richard Hamilton]

This is it: https://www.dension.com/automotive/products/car-multimedia-solutions/gateway-500

 

[Sparkatan]

Will mine be an older version as there is no box like the one pictured, just a black plastic housing with the usb, audio connectors and a short flying lead with the iPod connector. And a bright blue light.

[Richard Hamilton]

Look lower down on the page I linked to.  You will see the black plastic housing there.  The main box is probably tucked somewhere behind the glove box.  It think you need to start from the basics.  Check the fuses, then check the MOST loop, and that you are getting power to each unit (phone module, amplifier, etc.).

[Sparkatan]

Ah, didn't see the pictures below. Yes that's what my car had fitted to it. Can i get an installers'users manual for this?

[Richard Hamilton]

Look at the bottom of the page again, and you will see the user and install manuals there.....

[Sparkatan]

Sorry to be a pain Richard but you don’t know where I can get hold of a PCM2 manual from do you?

[Richard Hamilton]

Drop me a PM with your email address. 

[Sparkatan]

I know this isn’t related to this post but I removed my 996 S4 front end yesterday to  clean and inspect the ac condensers and radiators and found a Motorola antenna under the n/s headlamp and a loose thin wire with what looks like a sensor draped across the front of the car. Is the antenna something worth keeping and what’s the thin wire/sensor thing? It does look like it’s been retrofitted.

 

Quite a lengthy process removing the front end but the condensers and radiators were caked in filth and it was so satisfying doing th job.

[Sparkatan]

Many thanks Richard for helping me. I’m new to Porsche and it is much appreciated.

[Richard Hamilton]

It sounds very much like a tracker unit to me.  If you are unaware of a tracker subscription, and if it is connected to a power supply I would remove it if I were you, as they can often be the cause of battery draining.

[Sparkatan]

I don’t seem to be able to post a picture on here so i’ll email you it.

Edited October 7, 2018 by Sparkatan

[Sparkatan]

Yesterday I looked at my audio system in more detail. 

Firstly I checked the cd auto changer located under the front bonnet. There was power to it but nothing happening. I removed it and checked the small glass fuse and found it to be blown. I replaced it. The cd cartridge now ejects as it should.

In the process I found the two orange fibre optic cables to have been removed from the cd auto changer and fitted with a bridge piece.

 

I removed the audio system from the dash and found the Dension unit behind it. The fibre optic wires are connected to the audio unit and also go into the Dension usb box which is fitted in the glove box.

The audio system functions ok on nav and the map works.The radio channels are programmed in to the audio unit.

 

So, all in all it seems that everything is where it should be.

 

The problem I have is there is no sound coming out of the system. When I turn the volume button up nothing happens. There is no indication on the screen of volume level, which I would have thought would appear when the volume is adjusted.

 

My reckoning is the amplifier is duff. Am I right in thinking that?

 

Is the audio unit worth repairing? I take it that’s where the amp is located?

 

Or am I better off just replacing the system with something more up to date with current maps, bluetooth, etc?

[Richard Hamilton]

I agree.  It sounds like the amp has failed.  The amplifier is a separate unit, located in the front luggage compartment.  The most economical way is to get a second hand amp.  You'll find them on eBay, or try a Porsche dismantler like 9Apart.co.uk.  Another good source is boxsterbits.co.uk who often have them in stock.

[Sparkatan]

Looked at the amp today. It’s a 996 645 333 made in 2013 so must be a replacement. I took the covers off it and there’s no sign of burnt or overheated components nor is there a smell so maybe it’s ok. The fibre optic cable has light from one cable when disconnected.

Still get the error message, no amplifier, no cd autochanger etc.

Is there another amp somewhere in the car?

[Richard Hamilton]

There is only one amplifier.  I think you are at the stage where you need to get a diagnostic check by someone with a Porsche tester. I've heard good things about Porschtek in Leeds. Strasse have a good reputation too.