PCM System Error after battery disconnect..

[umog]

My battery died in my 996 (facelift) so I pulled it out and gave it a good charge for a couple of weeks. Upon reinstalling the car fires up straight away but now I have an issue with my PCM2 unit - it worked absolutely fine before with no issues at all...

Sometimes I get sound from the radio / cd and then after a while the error message appears and sometimes it happens straight away where there is no sound from starting the car.

The message is : System error: Phone, Amplifier, CD Changer not available.

I have tried 148 button press - sometimes this brings back the sound and sometimes not. The phone always seems to be 'initializing'..

I have also tried Main/Trip and FM/AUDIO/SET

I have pulled D9 and E6 & 8 fuses


PIWIS can find no fault in the fibre optic circuit but did seem to find some sort of 'grounding error' - Any idea where I should start to look?



I have a feeling it has something to do with the phone (was working fine beforehand) but am not sure where to start looking to try and trace the fault..

[coxy911]

Had same message on my pcm 2 unit a few weeks ago and in the end turned out to be a faulty amp. I see you've tried the fuse pulling trick and was no good,try leaving the fuses pulled for a few hours if not already done so as mine used to come back to life this way. The fibre optic chain goes from head unit to amp to cd to phonemodule and back to head unit, you could check each component by pulling the fibre optic cable and seeing if its lit red when your head unit is switched on.i.e if the fibre optic lead at your amp is lit red then you have output from the head unit, if the fibre optic lead at the cd changer is red you have output from amp etc. If you have a multimeter check also voltage to each component at the wiring harness.
Best of luck

[umog]

Great - thank you! I will try this over the weekend.

Are the fibre optic connectors easy to get to in order to pull them out? I believe the phone module is under the passenger seat..

Thanks again.

[coxy911]

umog said:

Great - thank you! I will try this over the weekend.

Are the fibre optic connectors easy to get to in order to pull them out? I believe the phone module is under the passenger seat..

Thanks again.

Yeah phone module is under seat, amp is easy to get to, just two nuts bolting it down so you can lift it out a bit to unplug leads. Cd will require a few plastic vanity covers to be removed first and again remove the unit to give better access to leads. Take care removing leads,they do have locking clips keeping them in place and will need to be flicked over 90 degrees to enable the leads to be pulled.
As a double check on the integrity of your fibre optic leads, simply shining a light down one end will show white light at the lead on next component in the chain.
Have fun.

[umog]

ok - have disconnected each fibre optic connector (amp / CD / Phone) and can see red light on each one.

Have pulled out PCM and checked fuse at back which is ok

I have also discovered as part of my journey that the right hand floor is wet in the rear passenger compartment (guessing drain holes are blocked..) It's a convertible.

If the phone unit isn't working because it has got wet then would this take out the amp cd radio etc even though the fibre optic loop is ok?

[Richard Hamilton]

umog said:

ok - have disconnected each fibre optic connector (amp / CD / Phone) and can see red light on each one.

Have pulled out PCM and checked fuse at back which is ok

I have also discovered as part of my journey that the right hand floor is wet in the rear passenger compartment (guessing drain holes are blocked..) It's a convertible.

If the phone unit isn't working because it has got wet then would this take out the amp cd radio etc even though the fibre optic loop is ok?

Yes, it will take down anything on the MOST ring. Best bet is to get a MOST loop (less than £10 on eBay) and use it to bypass the phone module. If everything else then works, you know it is the phone module. Search eBay for 'Porsche MOST loop'.

[coxy911]

As previous post I concur with Richard.
Try the bypass lead as it's cheap
.
Let us know how ya get on

[umog]

Update:

Diagnosis complete..

I fitted the bypass loop to the phone module in the floor under the drivers seat and the error message now reads only 'phone not available' The Amp and CD changer have started working again.

Source of the problem:

Rear drain was blocked in the water tray that sits behind the rear speaker and also at the bottom of the pipe where it exits behind the rear wheel arch splash cover.

Water had been overflowing in the drip tray behind the speaker and running from there onto the carpet below the rear seat. From there it drained down into the rear footwell and I guess at some point must have come into contact with the phone unit.

Speaker removed and tray cleaned.
Rear wheel removed and water exit cleaned and air blasted.
Water now runs from the cabrio hood into the tray and then out behind the rear wheel arch as it is supposed to.

Also cleaned the passenger side just in case..

Loop fitted to bypass phone module until I can source another.

PCM2 / AMP / CD changer also all removed and tested as part of the fault finding process!

[Richard Hamilton]

Rather than replacing it with an original module, you could get a Bluetooth module and bring it into the 21st Century. I had a ViseeO Mosto on mine which was brilliant, but here are several others - Nav-TV Tooki, Dension, or MoBridge.