Zipp4

Hi guys! Bought my 2012 958 Turbo about a month ago, love the car apart from the jerky shifting into 4th, but otherwise the only complaint was the lack of Apple Carplay. I went ahead and installed the Joyeauto kit a couple weeks back, after the first test drive everything appeared to be in working order and I buttoned it all back up and considered it job complete. However, the very next day I go to drive it and the PCM is totally dead, black screen, no response. After a few days and several expletives there are some signs of life - I'm getting the Porsche badge startup screen and the backup camera is now working again. After some more digging online, several folks had reported similar symptoms with a corrupted/faulty PCM HDD, I go ahead and remove the joyeauto board and the hard drive and viola, I have radio tuner and other basic functionality again, but obviously no maps or phone.

After this ordeal, I start to think that maybe I'd rather have a functional PCM over an Apple Carplay, and decide to revert to stock... this is where things go sideways.

Since the radio is more or less stabile at this point, I re-install the hard drive and overall it works ok. Still no maps, but whatever. My plan at this point is to install the latest firmware update and then leave it as is. I download the .iso, burn the dvd, and we're off to the races. Update goes smoothly for the first 90% or so and then it hangs and the dreaded "EMERGENCY UPDATE" loop begins. I go back upstairs to research this issue, which takes much longer than anticipated, and yatta yatta the battery dies and now the dash appears to be totally dead. I remove the hard drive and reinstall the PCM, still nothing. So at this point I'm pretty sure I've bricked the stock PCM, and I'm pretty clueless about where to go next.

I've ordered another PCM from ebay with the same serial numbers, but from a GTS, so I'm worried about the mis-matched VINs causing an issue with the software. So I'm throwing myself at the mercy of the court here. Any chance this replacement PCM will work, or am I going to be forced to take it back to the dealership? Any feedback would be greatly appreciated!

ShdwFx

I'm no help but the Joyeauto kit is something I've been considering. It's stories like yours that give me pause and realize that having Carplay may not be worth the risk. Good luck in sorting this out.

Boomer80

Welcome to the club both figuratively and literally. I had a very similar experience when I was installing the Joyeauto CarPlay, only I managed to break one of the ribbon cable connectors on the motherboard, which basically turned the PCM into a brick. I also had to purchase a used PCM off eBay. You WILL NOT be able to get the used PCM to work other than local radio stations. In my case I had to bring it to my local dealer and he was able to code the used PCM to my specific vin for about $75. This enables it to function normally after coding including the correct splash screen. My used one was from a CD and when I first installed it it came up with the diesel screen, and now comes up correctly for my CS. The only issue I continue to have is the dealer tech was never able to get the maps to work in Nav. That really doesn’t matter though because I now have multiple map apps to choose from thru CarPlay.

Finally, don’t give up on the CarPlay, it sounds like you just need to keep trying as one of the connections is most likely the cause. I got my CarPlay almost 2 years ago and at that time the LVDS cable that came with it was junk and got destroyed just trying to tuck everything in behind the PCM. It took me almost 3 months and numerous emails to get a replacement sent from China and the new one is much better quality. I can’t imagine not having CarPlay now. It completely updates the dated PCM into something resembling current for entertainment.

I also replaced the HD with an SSD and that is a good upgrade for little $.

yetti96

So my theory on getting a spare PCM just in case I screw up the carplay install, doesn't seem to be too wonderful if it still needs coding :/

Slam08

Wondering if you can just install an aftermarket stereo system now instead. Would an aftermarket stereo system work to replace the PCM? Since you’re stuck with a new PCM at this point maybe just change it to something else entirely? Not sure if this is possible though.

Zipp4

Thanks! I'll try to give it another go once I get it up and running again. This time I'll clone the hdd first, so that way I have a contingency plan if it doesn't work out. I guess the $75 dealer hit is fair all things considered.

Zipp4

I thought about that but the options weren't too appealing. The best one I saw looked like basically a housing to use some sort of tablet. Quality seemed a bit iffy, and I thought I'd miss having the physical buttons for the radio and whatnot.

Zipp4

That might not be a bad idea. I think my fatal error was letting the battery die during the software update - just don't do that!

...but if you need a cheap spare that can also function as a paperweight I might know a guy

schernov

Get the eBay pcm. Take it to dealer. They will program it. Worst case you are out of 1hr labor. Dealer will have access to all enablement codes assigned from factory.

don't sweat it.

ZenicaPA

Two questions, does the PCM contain the Sirius XM module and ....what are the steps to update the HDD to an SSD but leave everything else the same??

schernov

It depends on the pcm part number.

there is a thread in another sub forum about HD upgrade

Jaxmemo

Question on the topic of PCM replacement. In the same boat as the OP. Not paying attention during retrofit install (I’ve done it before without issues).

when replacing the PCM with another used PCM, do the part numbers have to match?

My 2016 has PCM 3.1 with part#958.642.963.x and a lot of reasonably priced 3.1 PCM for Cayenne have part#958.642.973.x.

schernov

technically no but you might loose or gain some features.

major pcm differences:
- with or without a Nav
- with or without HD radio
- with or without XM

there was also a hardware revision starting with November 2012 production which added
- with or without Internet services (Aha radio).

all of the above iterations are available in
- regular
- Bose
- burmeister flavors
so you can see how part numbers can explode in variety.

so if you original car did not have xm and you get a unit with xm- it will just not work

dealer can enable or disable needed features. If your car did not come with a feature you can purchase the enablement code. It comes from Porsche NA and dealer codes it via PIWIS.

I had my pcm replaced under warranty and while at it - I added internet services for the cost of the code and they programmed it in while doing the swap.

Jaxmemo

This is extremely helpful, thank you! Mine does have the features you listed above but I am going to do the CarPlay retrofit again which I’ve used 100% of the time in my previous 958.

is there a trick to knowing if it has navigation? I ask because I figured that may be important during resell in the future even though I’ll leave CarPlay intact.

schernov

There are buttons on the front "Navi" and "Map" on the main panel on the right.