PCM 3.0 REBOOTING CONSTANTLY

[SMARTTECH]

Hi all,
Put the fully charged battery back in my 997.2 TT this morning after removing it last november as the car was away for winter, and now the pcm comes up with the porsche screen for between 20-60 seconds and then goes off and starts again. tried holding down the info button but screen goes off again before anything happens or it switches over to the NM Automotive screen but still reboots constantly.

Anyone else had this and know what the problem is or how to reset it ?

 

[Slayer]

Had this issue and got it replaced under warranty. You can try re setting to hand over but will lose all your existing info. I tried but did not work but there are some on the net where it has been successful.
Likely the hard drive has gone caput

 

[Slayer]

 

[SMARTTECH]

I can't get past the Porsche screen before it switches off and comes straight back on with the Porsche screen.
It's like the buttons aren't working

 

[Slayer]

Likely will need replacement unfortunately.
I think it’s expensive but there are other alternatives you could get it replaced with like Kenwood etc that many owners have done.

 

[SMARTTECH]

Likely will need replacement unfortunately.
I think it’s expensive but there are other alternatives you could get it replaced with like Kenwood etc that many owners have done.

Will look in to weather it can be repaired as I have the NM Automotive unit installed for carplay as wanted to keep it looking original

 

[Slayer]

I agree . I like OEM looks too.
All the best

 

[SMARTTECH]

Cheers mate

 

[Jonesie]

I think NM repair them …..
Be interested to see how you get on as I have got the NM CarPlay on my 997.2

 

[SMARTTECH]

Will give them a call tomorrow and see what they can do

 

[gizlaroc]

Will look in to weather it can be repaired as I have the NM Automotive unit installed for carplay as wanted to keep it looking original

Would it not be best to remove that and see if it still does it before ordering a new unit?

 

[SMARTTECH]

Would it not be best to remove that and see if it still does it before ordering a new unit?

That involves a compleat strip down of the unit and removal of a Pcb and ribbon replacement to put it back to standard.

 

[gizlaroc]

Yeah, that's right.

But you may buy a new PCM 3.1, take out the carplay unit to put it in your new unit and then realise it is the carplay unit that is fried not the PCM3.1.


My first thought is that Porsche will have designed the PCM 3.1 not to fry itself when the battery is connected far better than some Chinese bolt on unit.

The fact is, you have some add on fitted to a unit that is now in a boot loop, so what causes a boot loop?

On these systems it is when all systems talk to each other and don't get a response, first thought on this is most connector no longer making a full loop, and I would still be checking that first, as if any one of the most connectors have come lose, or one of the fibre cables have been damaged, this is what tends to happen, boot loop.

However, you have also added something in the system loop with this 3rd party add on, if that has failed at all, or even if one of the cables has come lose, got a bit of corrosion on the ribbon (sat over winter getting warm then freezing it could happen) you could also now have this boot loop.

The fact it is booting at all makes me think the unit is OK.

I would definitely take it out, put it back to stock, check the most cable is still in the back ok, and see if it boots, if so, then clean the ribbon cable, pop the carplay back in and see how it goes. It could well boot straight back up.

No point buying a new PCM at this point though, yours could be fine.

 

[SMARTTECH]

Yeah, that's right.

But you may buy a new PCM 3.1, take out the carplay unit to put it in your new unit and then realise it is the carplay unit that is fried not the PCM3.1.


My first thought is that Porsche will have designed the PCM 3.1 not to fry itself when the battery is connected far better than some Chinese bolt on unit.

The fact is, you have some add on fitted to a unit that is now in a boot loop, so what causes a boot loop?

On these systems it is when all systems talk to each other and don't get a response, first thought on this is most connector no longer making a full loop, and I would still be checking that first, as if any one of the most connectors have come lose, or one of the fibre cables have been damaged, this is what tends to happen, boot loop.

However, you have also added something in the system loop with this 3rd party add on, if that has failed at all, or even if one of the cables has come lose, got a bit of corrosion on the ribbon (sat over winter getting warm then freezing it could happen) you could also now have this boot loop.

The fact it is booting at all makes me think the unit is OK.

I would definitely take it out, put it back to stock, check the most cable is still in the back ok, and see if it boots, if so, then clean the ribbon cable, pop the carplay back in and see how it goes. It could well boot straight back up.

No point buying a new PCM at this point though, yours could be fine.

If I hold down the info button to access the carplay it comes up on the screen showing my correct location on the waze satnav and the song playing on Spotify so the carplay side of it seems to work all be it I have no sound and the unit still keeps rebooting. Press the info button again and it's back to the standard pcm3 but only get the white porsche screen and never seems to get past this point. Will speak to NM Automotive who supplied to carplay kit and see if they have any ideas as I'm sure the repair pcm units as well.

 

[gizlaroc]

OK, getting a bit more info now.

No sound.

I would be checking the amp, wherever it is located? To me it sounds like the amp is faulty, hence the MOST network loop is now broken.

To test this you can take the MOST in and out cables out of the amp connector and hold them together, use a bit of sellotape, and see if the unit then boots up and stays on.

Also, make sure no fuses are blown, if the amp is on a different fuse to the PCM, it may have blown that will give you exactly the results you are seeing.