I've been unable to start the car for a few days in a row.
Had to jump the car each time.
Replaced the battery, issue remained.
Figured something must be draining the battery overnight.
Did some investigation and finally found the culprit by removing the fuse for the PCM.
Car starts up every day with the PCM fuse removed.

Removed the driver side center air vent so I could check to see status of power to the PCM (there's a yellow glow visible from the top / side of the PCM indicating some power to unit).
Turned off PCM using the left PCM ****. No image on screen, but still glow from inside the PCM.
Remembered that PCM stays active for a while after shutting the off the vehicle, so I let it sit for a few hours.
Checked and the inside of the PCM still had the glow (did not open door, just viewed from outside the car).
Somehow, power never gets completely shut off to the PCM.

Any clues/suggestions to the cause on constant power to PCM and fixes?
BTW: No aftermarket (Isudar) card installed.

Thanks in advance everyone.

 

There is a way to do a hard reset that may help. I don’t remember the procedure. Dealer should be able to provide instructions. Good luck!

 

Tried to do the Reset / Handover process.....Did not solve issue.
BTW, procedure is: hold INFO button until Porsche Crest shows up on screen, push CAR button on PCM. On the screen, sequentially touch OPTION, Set PCM, Vehicle Handover, YES, YES when prompted.
Process is in the User Manual.

Coincidentally, the PCM seems to be rebooting every few minutes. Not sure if the two are related.
Noticed also that if I turn off the PCM with the left Power/Volume ****, the PCM will turn on by itself after a few minutes.

Any more suggestions to debug or fix issue(s)?
Thanks

 

If your pcm restart all minute it's a hard Disk problem. You can change ths DD it's not a Sata but serial Pata. 64 Giga it's good in SSD too

 

Understand that the continual reboot issue is probably due to HDD problem.
Will resolve that by replacing the HDD with a SSD.

How would the HDD error/failure be related to the "Always ON power to the PCM"?

BTW: Other threads about the reboot issue were resolved by having SiriusXM resend their signal to the PCM.
After an extremely lengthy chat with SiriusXM "support" finally got this link to have the signal resent: https://care.siriusxm.com/retailrefr...#/refreshradio
You need to have an active XM subscription for it to work.
I don't, so couldn't use the "resend signal" to help me out.
Hope the link saves others some time/frustration.

 

The PCM reboots every few minutes because it's not getting past all of its startup routines. It's only option is to keep try to run those routines. Common known problem.

There is a guy here that sells SSDs all preprogrammed and ready to go. Very reasonable...about 180$ IIRC.

 

Swapped out the HDD for a SSD.
Seems successful since the PCM boots up, AM/FM/SAT are working CD/Jukebox/Aux all show up.
Still reboots every few minutes so I tried to update the PCM (from 4.73 to 4.76) per other threads.

Copied iso files to DVD.
Tried to insert DVD into slot, but unit wouldn't accept it.
No other disc in unit.
Possibly the CD is broken...lots of resistance trying to insert the DVD.

Copied iso to USB stick (FAT32 format, 16gb, no other files on stick).
No action using USB port in center console.
AUX shows up as Source, and in Options...Aux and BT Aux appear (only Aux box checked)
Some threads say that the AUX port needs be activated......but to do so requires sliding a disc into the CD!

So, I'm in a Catch-22.
Suggestions anyone?
- replace CD unit?
- can AUX be activated another way?
- source a SSD with 4.76 installed?
- ???

Thanks everyone.

 

Got the CD/dvd reader on the pcm to work. Loaded the disc with the iso files and it seemed to complete, but pcm now in emergency update mode. Tried reinserting disc multiple times, but always got “invalid update medium”. Tried using various usb sticks (FAT32) with the iso files loaded on them, but no response from pcm…. The status light on the usb sticks never light up to indicate activity. Any suggestions to finish the procedure and get out of the emergency update mode?
Btw: seems like wants the PCM31RDW400.def file. Thanks.

 

Have you try to reinit the pcm?

 

If you mean the Reset/Handover procedure, YES. Unit always stays/returns to emergency update mode.

If not, what are the steps for the reunited procedure? Thanks.

 

I don't see where is the problem, sorry.