BlazinPond

I've had this problem of the PCM rebooting starting this past Tuesday (described above).

What's ironic to me:
Today, I turned off the bluetooth feature on my iPhone 6+ and.....no issues with the PCM rebooting every few minutes!

Coincidence?
It really doesn't make sense to me if it truly is an XM radio update issue.

IMO, somehow my issue seems to 1) occur when my phone's Bluetooth is on 2) have something to do with the latest IOS update on my iPhone 6 downloaded the day before my issues began.

Tucson_Jim

Same issue. Once i linked my iPhone6 BT to the Cayenne, it worked fine until I updated to iOS 8.1. Then PCM began rebooting every 2 minutes. Kept doing it even with BT turned off. I deleted the phone from the PCM phone list and the problem disappeared. Re-added and after pairing the problem re-surfaced. Must be the PCM firmware, but I'm going to wait a bit so the tech database at Porsche catches up. Interesting, but not surprising... same thing occurring on the Audi forums.

TGED

We have iPhone 6+ with iOS 8.1.1, no problem with the PCM.

jfr0317

Do you also have XM Radio?

CAVU

My PCM has been rebooting off and on this past week. When I purchased it last month, the dealer has service records that the PCM was updated. I've been keeping the PCM bluetooth off and have had no reboots. I did not have a reboot yesterday until I turned on the PCM's Bluetooth and turned on my blackberry Z10 Bluetooth for a phone call. No reboot. I stopped, shutdown the car for fueling and then restarted. Very shortly after restart, I got a reboot, I turned off the PCM Bluetooth and no more reboots. My wife's Iphone 5's Bluetooth was off the entire time.

Time for a trip to the dealer. Service advisor told me that they had noticed reboots after the XM drops a signal and tries to re-aquire, others have noted Iphone 6 updates as a culprit. Maybe by the time I get to the dealer the mothership will have figured this out.....Nahhhhhhh.

TGED

No XM Radio.

stumil

Took Cayenne to dealer today for PCM software update. Rebooting issue is now fixed.

amfp

Me too last week. Dealer installed latest software from v2.41 to v2.47

PCNA claims its because of iPhone 6, even though it worked fine for the first two months owning the iPhone 6. As precaution with new software, I deleted my iPhone from the PCM, and then reloaded it fresh with the new release. Been about 500 miles, no issues.

pwhite52

Dealer updated PCM today and rebooting has stopped.

jfr0317

My dealer updated the PCM on our 2011 Cayenne S today, and the rebooting problem has been fixed. The dealer once again said the issue was caused by an XM Radio-initiated XM software update.

As another data point regarding whether the iOS 8.1.1 update was causing the problem, when we were visiting our daughter over Thanksgiving (and before getting the PCM update today), we tried the car with our daughter's not yet updated iPhone only, and the rebooting continued to occur. In other words, prior to today's PCM update, the PCM was rebooting whether an iPhone running iOS 8.1 or iOS 8.1.1 was connected.

Tysoncn

I tried to research about it. I have seen that there are a lot of problems with the pcm or stereo whatever you want to call it but mine seems slightly different , my head unit turns off for up to a month sometimes and then it turns on out of the blue and works great for a while then it'll flicker and turn off sometimes it'll come back on the next time I use the cayenne other times it'll work weeks down the road but I have noticed it works more often in the winter then it does in the summer which i found really odd my dash screen always works but flickers a little and the heat/ac acts weird as well it'll go high and low randomly everything started to happen at the same time , could it be a battery issue or something bigger or what?

Charles Dunn

So the PCM in my 2013 Cayenne started rebooting intermittently. I figured out that I can modulate the problem by blowing cold AC (<65) out of the lower vents for a few minutes. If I turn AC off the pcm resets again after 5 to 15 minutes Clearly heat related, but not sure what component. Im this king power supply but it's a guess. Has anyone seen this? Any recommendations?

Dilberto

PCM software corruption, due to nearly-fried radio mainboard from repeated heat-cycling(always use ON/OFF button!). Either send it to Becker Autosound LLC(NJ)... or, go with Android-based system.

Chris C.

Hello all - "rebooting" this discussion, 2020 version.

Has anyone found a resolution other than full PCM head unit replacement?
- Software upgrades work?
- Anyone had their PCM rebuilt by Becker @Dilberto ?

My 2013 C2S is 6 months out of CPO (naturally) and just started the auto reboot feature every 2-5 minutes.
- Battery is def in need of replacement (new one in hand)
- I have an Iphone 11pro with latest software push
- PCM version is 3.43
- CD changer and maps work - most times it's tuning XM radio
- XM radio recently renewed but has been active for 4.5 years on this car

Thanks for any help/advice here. Not going to spring for a new OEM piece but there's always the dismantlers I suppose...

EDIT: Nice rennlister pointed me to the "hard reset" option in the PCM. Will try but curious how others have solved this, and/or how to prevent it??

Annie Nomous

My 2011 cayenne hybrid PCM started doing the constant restarting every few minutes last week. Due to quarantine only driven the car a few times over the past 10 weeks. Also, when I start the car I get a yellow warning message “battery protection while car is parked “. Can’t help but think the car is trying to tell me something. I wish it would just give a clear error message