max540i

While being serviced by dealer, facia on volume control **** disappeared, but, no problem, car is CPO'd, so they ordered a new ****. Problem is that they couldn't get the new **** to function. Specifically, they couldn't get it turn on/off and adjusting volume requires side pressure. When they swap back the original ****, they get the same problem. Apparently installing the volume **** is tricky. Dealer's proposed solution is to replace (under CPO) the PCM. Seems excessive. Anybody know the trick to replacing a volume ****?

Petza914

The PCM ***** just pop off and are replaced by pressing on the new one. Sounds like maybe they damaged the left shaft and switches trying to get the old **** off.

Edit: Incorrect info provided here - see additional responses.

Bruce In Philly

Not on the 09 and newer... if you try pulling it off, you will break the PCM head unit. Sounds like someone tried to do just that and broke the mechanism inside.

https://rennlist.com/forums/997-foru...pcm-*****.html

I never saw a radio that had bolted on *****..... weird.

Peace
Bruce in Philly

Petza914

Thanks for the correction Bruce. I've never had my Cayenne PCM3 ***** off and my 997s are .1s so PCM2 where they just pop off as I recently replaced them on both cars. You would think the dealer would know this though and wouldn't have tried to just pry off the PCM3 *****, but I'm thinking maybe that's exactly what they did, which is why the push function doesn't work anymore.

max540i

Sounds very feasible ...

Anybody know of any pitfalls related to PCM head unit replacement?

Petza914

Should be plenty of threads on this. Using a MOST adapter I think you lose the ability to fade front to rear, maybe the in-dash compass display if you have one, and if you have multi-function steering wheel, I believe that functionality is lost too.

If replacing the head unit, I think it makes sense to completely change the entire stereo system with upgraded speakers and subs, traditional amp(s) that take the preamp outputs from the new dash unit, etc If your car has Bose, the problem with the Bose system is the communication between the PCM and the Bose Amp uses fiber optics instead of normal preamp connections so you need an adapter (like the MOST) to make the new head unit work with the Bose amp. If your car doesn't have Bose then things become quite a bit simpler as the non-Bose cars use a normal connection system and traditional amp.

max540i

Sorry, I should have been more precise, I'm looking for pitfalls related to the Porsche dealer replacing the broken PCM with a stock PCM. Fortunately, I still have a month of CPO!

Wayne Smith

You have exposure ... the PCM will not be replaced with a new PCM, but with a serv (service) grade part. This part will have been returned to Porsche for cause, and repaired. Repaired may not mean fully fixed.

In other words, get in writing that this was replaced and should take a new warranty that exceeds the CPO.

Bruce In Philly

Also.... ask if the Porsche two-year warranty is in effect for it. Used to be every part came with a two-year warranty regardless of the year or condition of the car.

As for pitfalls..... Hmmm... you could ask for the latest firmware and map software as part of the deal. At a minimum, you don;t want older maps that may be in this unit... so use this as a ploy to have them update the unit.... The PCM unit has to be "coded" to the car and there are some options, such as Sport Chrono that has to be activated... or not. When you get the car back, quickly go through all the functions to ensure it is integrated with the car..... such as nav and radio appearing in the center instrument cluster..... the unit calculates trip information..... you receive XM's test broadcast.... the USB port in the cubby at your elbow works..... etc.

Peace
Bruce in Philly

mike cap