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Mike S.
Mike S., ASE Certified Technician
Category: Porsche
Satisfied Customers: 7568
Experience:  Porsche mechanic.
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The battery did test out at 12.7V, which according to the

Customer Question

The battery did test out at 12.7V, which according to the tech is optimal. I think it sounds right too, but I'm no expert.I asked the dealer to clarify why he thought I needed what I did. He stated that the headunit takes the new software and updates, but it keeps doing the same thing as before - restarting every 10 seconds. They said if they try the software fix and it doesn't work, that they then start changing out the hardware, ie the headunit.He also stated they tried to program the trunk and the unit wouldn't take the programming, thereby beeping 3 times quickly.However, I keep telling him that when the radio works, the trunks works perfectly too. I think there is something related going on, but they state they don't think so. I hope you can help me figure out the issues with my 2012 Panamera RWD V6.Car was working good. After not driving it for one week, then starting it, the PCM continually tries to reset itself every 10-15 seconds.The exact issue can be found in this youtube video:
You TubeThe weird thing is, every now and then it will magically work, usually after being left overnight.The interesting thing as well is that the trunk will beep 3 times when the PCM is in the rebooting state, whereas if the PCM working, the trunk works correctly.Is there anything I can do or check? I took the car to Porsche and they want me to replace the whole PCM for $4,000, and replace the trunk module for $700. The battery and charging system seem to be fine. I even bought a new battery, it didn't help matters.The car has less than 20K miles, I can't believe these issues are happening.
JA: Have you checked the battery, particularly the terminal connections? Are they corroded?
Customer: the car is very low mileage, less than 20K, and lives in Southern California...we really don't get rust here
JA: Are you fixing your California yourself? What have you tried so far?
Customer: it does have a new battery
JA: Anything else you want the mechanic to know before I connect you?
Customer: that's basically it, thank you
Submitted: 1 month ago.
Category: Porsche
Expert:  Mike S. replied 1 month ago.

Hi, I am Mike, welcome. I'm reviewing your question.

Expert:  Mike S. replied 1 month ago.

There is a technical service bulletin out on pcm rebooting,

The Porsche dealer should have known about this, did they try this?

Customer: replied 1 month ago.
they tried to update the software but they said the headunit was still acting the same after the update...
Expert:  Mike S. replied 1 month ago.

I suggest you read that entire article, "

The DBase_Reset software erases the corrupt Data Base in the PCM. This will prevent

rebooting during the update process, which can result in a PCM "stuck" at the Emergency

Update screen."