WCH BOS

I'm having some issues with the PCM in my 2015 TT and wondered if anyone else has experienced these issues.

1. PCM reboots randomly while driving
2. Map cannot load in the main PCM screen or in the small screen next to the tach
3. iPod connects about 50% of the time

I think the last issue is separate from the first two, which are new, while the iPod issue has existed ever since I got the car.

The software on the PCM was updated last summer.

The car is going in on Monday but any insight would be appreciated.

worf928

PCM in the 981 was replaced under warranty before the end of year one. Techs told me that they replace a lot of PCMs. (Where "a lot" means what? I assume it's an infant mortality issue.)

Spastic reboots might be a power or ground issue. But inability to swap bits with the dash suggests something less simple. Good luck.

WCH BOS

I suspect you are right on the mark and a new PCM is in my future. I think the maps don't load in the dash because the HD is toast in the PCM and so the dash can't load anything.

I hope it isn't more serious although a 991.2 with the new PCM and steering wheel has some attraction. I suspect it won't come to that.

Michael_s

I had a Panamera that kept rebooting. It needed a software update for the XM/Sirius. My TT VIN is calling for a software update. Tech said don't do it unless PCM is acting weird as they crash a lot then need new PCM. Service will take care of you. Worst case new PCM.

WCH BOS

Thanks. They did the XM/Sirius update last summer unless there is another one. Agree with you about them taking care of it and worst case scenario a new PCM.

Will update when there is a diagnosis.

MJM911

By any chance did you happen to drive it during the extreme cold weekend we had a couple of weeks ago?

WCH BOS

Nope. Car was garaged until today when I decided to take it out since it was dry and sunny.

911tts-LA

I have the same issue. PCM reboots by itself when I am playing CD or USB but not XM. It only happens once in a while. No extreme cold weather as I am in LA.

WCH BOS

So the diagnosis is that the car needed a software update. I thought it got one last year but I'll be happy if this is all it needs. Hard to understand the timing but as long as it works. Picking it up later today.

Michael_s

Hopefully this solves the issue. Keep us posted.

MJM911

I hope that's all it is for you and it solves the problems the experienced.

Since our cars were built with a few weeks of each other, when I come out of winter storage and I go in for an oil change, I will ask about this update. If they provide you a Porsche Service Bulletin number, please post it here.

WCH BOS

So some bad news. Although they did do the software update (version 4.73 updated to 4.76) and told me that everything was working fine, I tried to go to the map as soon as they brought my car down and maps still don't load in the PCM or the dash. I think they just didn't check to see if they had solved the problem. My suspicion about the timing of these problems seems to have been correct. Looking like a hardware problem - my uneducated guess is a dead hard drive.

So I get the Camry loaner to drive until they figure this out. New PCM seems more likely now.

worf928

This, when it happens to me, makes my intercranial pressure spike. It's not like verification is a minor step in the process. Then I get depressed and cynical about the future of humanity...

They will need to get approval from PCNA. Likey PCNA will make them jump through several hoops of resetting, re-installing firmware, etc. And, PCNA doesn't pay the dealer for jumping through the hoops. Since the techs are forced to do this for free - they aren't salaried employees - they have to work it in between paying jobs. Obviously, you'll need to be politely persistent with the 'are we there yet?'

Given that you got a Toyota as a loaner I guessing it's Ira in Peabody?

WCH BOS

I'm trying to work through the issues with them. You are correct that they need to contact PCNA. The reason I have a Camry is that I didn't schedule this ahead of time - the dealership (not the one mentioned) that I am at usually gives out Cayennes or Panameras as loaners. We'll see what they say today.

WCH BOS

Waiting for approval from PCNA to replace the PCM. A couple more days before the car gets fixed.