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PCM 3.0 rebooting?

mikee

Well-known member
Joined
30 Nov 2008
Messages
49
Hi all

So after a month of issue free motoring I have my first problem.

Last few days, intermittently, and with no regular frequency the PCM will shut down, reboot with the Porsche logo and then return to the last screen it was on before rebooting, but returning the radio volume back down to a lower level.

Is this a common issue? It's in a 2010 C2S.

Also, are you supposed to be greeted with the Porsche logo everytime you put the key into the ignition after unlocking, as mine doesn't always. Most of the time it goes straight into the last screen you left it on. Not sure if that's correct or not?

Hoping this can be resolved by just removing a fuse to clear a bit of static or something!

Thanks
Mike
 
I don't usually see the Porsche logo, just once in a while. Mine went through a short phase of rebooting and then went back to normal with no action taken.
 
I've had my (2009) car for just over 4 yrs and had no problems at all with the PCM until last week on a longer drive when I'd been in the car listening to a CD for over two hours.

Towards the end of the CD during the last song, it switched off for no reason, got the Porsche Logo, switched itself back on and went to the second song rather than the first. I thought it might be dirt on the CD or something but then it did the same thing switching off and on with the Porsche logo coming up again.

I switched over to the radio and it went immediately onto AM rather than pre-set FM and played white noise / static until I tried to switch it off.
It wouldn't switch off, volume control didn't work. Then after a few minutes it kept switching off and on with the Porsche logo.

I eventually stopped for a coffee and turned the engine off. when I came back the CD player started as normal then I got the same routine, switching off and on by itself.

Leaving the car parked overnight it was fine the next day ?? I'm wondering if it was heat related ....i.e. playing for too long? or maybe just the warning signs of something due to break down completely.

Any similar happenings with you guys or any thoughts ? thanks.
 
Never happened on mine *touch wood* in 3 years.
Have listened for 6 hour periods. Car is December 2009.
 
Do you have an IPhone and if yes which one and have you had it linked to the PCM? If yes I can explain - if not I'll shut up :)
 
Richtw .. im intrigued .. more details please :D

Porsche Logo .. kinda normal ..

rebooting .. hmm .. only 2 things i can think of ..

1/ There is a poor power lead connection which is randomly disconnecting the 12 volts to the pcm hence it will reboot .. never seen it but possible .

2/ Faulty pcm .. in which case remove and send to one of the repair companys is the best bet .. replacing is Not a cost effective solution .

I have seen number 2 im afraid .
 
Right here goes - my pcm was rebooting from time to time, but it only seemed to coincide with my phone being in the car! Phone not in car never happened so I got curious! In short there seems to be a bug with the iPhone downloading the phone book to the PCM over Bluetooth. I turned Bluetooth off - not happened. Turn Bluetooth on occasional reboot. Seems to be a bit of a known problem! I can live with it though :)
 
Aghh this rings a bell .. too many tunes / music files on the phone .. the pcm cant download them all so it gets upset .. it keeps trying but not enough space ... i need to do a bit of digging .. im sure ive got some info on this somewere .. job for the weekend methinks .

Phone book is a new one on me but i need to research it i think .
 
It downloads the contacts from mine. I only have a couple of tunes on the phone.
 
Yup downloads the phone book from mine too - but occasionally it hangs and the pcm reboots! It has only ever happened when my phone has been connected!! It's odd!!
 
First bit of stuff i found on this ..

The PCM can store phonebook contact information directly within the PCM. A maximum of
2,500 phone numbers may be stored. If there are multiple phone numbers for each contact,
the total number of contacts that can be stored will be less.
 
For me personally it is not the number contacts it is the data transfer from the iPhone X. The pcm does not always like it!
 
PCM Reboot

I've experienced this issue on several occasions on my MY2010 997.2 and have been tracking various forums (fora?) to see how to resolve this issue. What I have found is that it is often argued that it is caused by:

- intermittent PCM hardware failure
- too many contacts being downloaded into PCM from your phone

..but exasperatingly there appears to be no consistent failure modes.

Because my failures usually occur at the same geographic location, I have another theory on this issue. I believe it is due in some cases at least to coupling of magnetic fields from major power lines under the road (for anyone in the defence electronics industry refer to MIL STD 461, Radiated Susceptibility, RS101). I suspect that the shielding of the PCM is not perfect and the magnetic field emanating from the power feeder cables to e.g. a shopping centre where it generally occurs are coupled into the electronics and cause a system reboot. I'm not sure how else you explain the reboot at the same location! To avoid this EM coupling the complete PCM would need to be effectively encased in a faraday shield AND the interconnecting cables screened and fed into the PCM via RFI filter feed-through connectors...but then I worry that shielding the complete PCM would lead to heat issues and in any event it's hardly a practical solution!

Interestingly, I had the same issue in my previous car (an E92 BMW 335i) at the same location and BMW cured the problem with a software update.

In recent times, I've done some more research and discussed the issue with our local Porsche dealer. It turns out that depending on which version of PCM software you have an update to Versions 4.76 (for PCM software versions 4.XX) or to version 3.43 (for PCM versions 3.xx) will apparently resolve the problem. The software update is undertaken via a DVD installed in the DVD drive in the head unit and PIWIS is not required.

Our local dealer is prepared to do the update BUT has advised that on some 5% of occasions, the software update fails and bricks the PCM...a risk I'm not sure I'm prepared to take. Far easier to simply avoid the area where the problem occurs....sigh.
 
Re: PCM Reboot

systech1 said:
I believe it is due in some cases at least to coupling of magnetic fields from major power lines under the road (for anyone in the defence electronics industry refer to MIL STD 461, Radiated Susceptibility, RS101). I suspect that the shielding of the PCM is not perfect and the magnetic field emanating from the power feeder cables to e.g. a shopping centre where it generally occurs are coupled into the electronics and cause a system reboot. I'm not sure how else you explain the reboot at the same location! To avoid this EM coupling the complete PCM would need to be effectively encased in a faraday shield AND the interconnecting cables screened and fed into the PCM via RFI filter feed-through connectors...but then I worry that shielding the complete PCM would lead to heat issues and in any event it's hardly a practical solution!

This is a very interesting theory and one which I actually thought about while driving when it went off. I was wondering whether it could have been affected by an external influence, e.g. Overhead power cables too close to the road, or military grid systems nearby etc. but your comment about the defence electronics standard MIL STD 461 may well be right , I'll have to search my route and see if I was anywhere near a military base, or area that required lots of power (underground cables). I'll keep you posted.
 
Thanks for the replies. I think the bluetooth thing may be the problem.

Both me and my other half have iPhones that are connected via Bluetooth to the PCM (way under 2500 contacts though), I also have an iPod that is plugged in to the iPod input under the armrest which has been temperamental.

Have disconnected the bluetooth today on the phones and so far hasn't crashed. It's definitely not a geographical issue for me as it's happened in a lot of different areas.

I also have a weird issue (that I presume may be connected) where if you stop the car and shut off the engine, but leave the key in the ignition with the PCM on, when you start the car again the audio shuts off completely. The unit stays on and functions as normal but with no sound.. so weird.
 

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