Hi,

I have a 2012 991S cab and my PCM started power cycling and won’t stay on for more than
a minute. It turns off after a min and immediately turns back on. It keeps doing this.
Any ideas what it might be and if it’s fixable or do I need to replace the unit with an
aftermarket unit? If I do, what do you guys recommend for aftermarket replacements?

Thanks,
Jon

 

Its been a known issue that often requires replacement - 1st try holding INFO and SOUND buttons simultaneously for 10-15 seconds to Reboot/Reset. You can also try updating to the latest version of Firmware which is v4.76. Check YouTube on how to confirm what version you are currently on and for a demo of how to update. You can buy the update disks online or go to a Porsche Dealer. If you have Bose you can purchase a universal replacement kit to run most aftermarket Double DIN units - Suncoast Porsche Parts has an option to consider.

 

So I did the reboot per the instructions above but it didn’t work. Is there any point upgrading the firmware or does it need replacing at this point? I don’t want to upgrade and pay for it to fail again. Might as well go aftermarket now?
What’s the recommended latest aftermarket for these cars? Something that will give me a bigger screen, CarPlay and backup cam would be a nice upgrade now!

 

A firmware update likely does not solve your issue. That said if you went to a dealer they might update for free if you have a relationship. I like Kenwood - for example DDX9907XR for wireless but many good options out there from Pioneer, Sony, JVC and Alpine. A member of the Rennlist Forum is selling a used Alpine conversion he pulled out - check the Marketplace if interested

 

Check out the thread today in the 991 forum on Rennlist titled

PCM Problems in 2015 991

 

Mine did the same thing starting on 05/21/2020. I am hearing it was do to an SiriusXM push yesterday. I fixed mine by doing this:
I pulled the PCM fuse from the left fuse box and waited about 30 minutes. Then put the fuse back in and performed a factory reset. I also had SiriusXM refresh the signal as well. Now everything is back to normal and has been working great all morning.

I was told it had to do with some update they did on the 21st that messed with the PCM.
I have PCM 3.1 V4.76, 2015 Boxster S

 

Common Siriusxm issue that started. Long thread and remedy to fix it on rennlist 991 forum. I had the same issues also.

 

Easy but PITA fix.. Worked on 2 P-Cars for me. On PCM press and hold Info button until PCM reboots. Then press Car>Option>Set PCM System>Reset PCM>Vehicle Handover>yes>yes. You will now have a blank slate. You will have to reset everything. Refresh signal from SiriusXM, pare phones, station memories, nav settings, etc.

 

Yup it worked! Thanks all!

 

Is it safe to unplug PCM fuse and continue driving without having other issues? Since the PCM reboot not fixing the reboot issue.