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PCM 2.1 Error

roberts

New member
Joined
11 Jul 2012
Messages
7
I have recently had an error pop up with my PCM and keen to see if there is a self fix or anyone has had the same experience.

On power up an error message is displayed saying Navigation, Amplifier, CD Changer not available.

Click confirm and you are into the normal interface however there is not audio being played.

Occasionally it will randomly play audio for a few seconds then resumes to stop working. CD is still playing (evident by track counter going up)

When no audio is being played I also get a random "crack" from the speakers and picks up interference from my phone.

Anyone shed some light?
 
Just a guess, but it sounds like a possible problem with the MOST network. Is anything unplugged?
When fitting a Dension Ipod interface recently, I got the same message when I swithched the head unit on with the MOST disconnected.
 
PCM Error

I was about to post asking advice on a problem I have, and I found someone had exactly the same problem back in 2012, so saved me some typing.
I am geting the same error message - Navigation, Amplifier, CD Changer not available.

There was one reply back in 2012, but i wondered if anyone has had the same problem since then, and how to deal with it.

Thanks
 
It does sound like a most optical loop issue.(thickish orange 'cables')

Depending on options fitted, it could be behind pcm, @cd changer, @bose amp, @nav dvd or under drivers seat phone module. Oh, or @ mobridge or dension - if fitted.
 
Is that something I can check and do myself?
What is MOST?

Thanks
 
Absolutely Rob , should be DIY.

MOST is the lan-type Comms the car runs (at least that's how I think of it)
2 X thick orange optical fibres which 'loop' all the above components together.

I'd start under the driver's seat - move to the max extent possible up, and either front or back to reveal the units beneath.
If found and ok, move to next unit.
Hth
 
Thanks, i will check under the seat , should be easy but how do I get to the other units?
 
If you think of MOST as a loop with items conected then you pretty much understand it ..

Soo .. pcm sends a signal to the CD .. this sends a signal to the Nav .. this sends a signal to the amp .. its then returned to the PCM .

If anyone of these items doesnt resend the signal then it all fails and you get what you have .

First check is with a tester .. fault codes and a MOST check.

Second and we fit a bypass Most loop at each item , it kinda knocks that item out of the loop as it bypasses it .

The usual item would be the cd Stack system or the amp .

Short of checking for kinks in the MOST lead .. which never happens you are going to need a tester to figure this out .

I will also add .. some times codeing can get messed up and cause this .. there is a list or actual items and nominal items fitted .. that means what the car thinks is installed and what the car can talk to .. if the order of this gets messed up then again you will have a similar fault to yours .

If you can get a MOST bypass lead then you could use it on each item without a tester to try and diagnose it .. but to be honest .. i struggle with faults like this on the audio system and i wish i could just get a garage to fix it :)
 
Now display screen is hot

Thanks for the tips.

I looked under the drivers seat - there is 1 unit under there, but i couldnt see what it was and i couldnt see any orange cables.
So i looked under the boonet and behind the dash. I found a navigation unit and a CD unit. I can also see a pair of orange cables coming in from the left and going behind both units, and the same from the right - so I assume this is the loop. However I could not get in there to see if there we good or bad connections.
To be honest I am just living with it now. Most days I get the error, and have no radio - but it always clears itself after driving for a short while, and just comes on all of a sudden.
What is worrying me though is how hot the display screen is geeting - wasnt sure if this was normal as i havent noticed it before, ir whether it could be related to the radio error and could be a potential hazard? I ejectd a CD yesterday and could hardly hold it as it was so hot.
Any advice welcome.
Thanks
 

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