JPPoulin

Looking forward to what they say. I happen to be an electronic engineer and my least bad guess is that the board responsible for radio & app in the PCM has issues (but nav module and rest still works)... I'd be surprised if the problem is outside the PCM

lagunatich

More background on my issue . . . the amp under the passenger seat had some water exposure due to plugged drains. I had the amp repaired and tested, but the no sound and sourcing issues remain. Stay tuned.

JPPoulin

This is super interesting and highly pertinent to my own situation

However if you are talking about the module under the driver seat this one is the rear control module and not the amp. I have completely flooded this module a couple of months ago and now most of the rear of the vehicle is non-functioning such as the trunk opening, The convertible top, And the rear break lights

What information do you have that this could affect the PCM module? Given that you and I both have the same problem with the PCM radio and we both have seen damage on the module underneath the passenger seat I wonder if there is some functionality of the rear control module that would explain my radio amp not working.

See my other post about the rear control module being faulty and see if you have any similar symptoms.

lagunatich

Well, in my case, no issue other than audio. All other functions you report - trunk, top, brake lights - no issue.
The under passenger seat unit is a Bose audio amplifier. It appears as if there was maybe 1/4" of water in the floorpan under the seat during recent rains. After doing research I found the top drain "valves" were somewhat clogged, though we had heavy rains when this occurred. Fortunately our driveway leans to the right, so the driver side module was not impacted. I found a YouTube video to access and clear the valves. Very easy task to do if you know a few shortcuts.
I am thinking PCM simply because I don't know what else the issue could be.
Other than audio, the car is 100%.

JPPoulin

I made a mistake in my previous post saying it was the passenger seat module being the rear control module but it is the driver side one. Mine is completely destroyed and causing the issues with the roof and the trunk and the brake lights as I mentioned. I fixed the post.

However I did not know that there was the amplifier under the passenger seat. Given that the car did get some rain on both sides there is a possibility that the amp Has been damaged as well in a previous flood. Do you know if all 981s have this Bose amp under the passenger seat or is it an option?

Thanks for posting the evidence that you have seen it helps me debug what is going on. Please share what new evidence you have when the mechanic looks at the issues.

lagunatich

I think the Bose system is an optional upgrade . . . but not sure.
I hope to do a electrical systems check within the week . . .

JPPoulin

Myself I removed the driver's seat to remove the rear control module as the module was so bad that it would drain the battery quickly and force all kinds of weird behaviors on the electronics of the entire car. what a disaster. It is incredible to me that such an awesome automaker would put sensitive electronic equipment at the lowest point inside the cabin of a convertible car.

I haven't looked under the passenger seat to see if my car has any amplifier under there. However given the problems that I have with the sound not working and what you reported as evidence it seems likely given that my driver's side module got completely soaked that the passenger side might have some water damage as well.

Thanks for sharing what has happened on your car as it gives me lots of clues as to what is wrong with mine. I hope the repair bill is not too expensive keep me posted on what happens.

You said you had the underseat amp fixed and the problem remained? How will this next leg of work be different than fixing the amp?

Jim981CS

I purchased my 2014 Cayman S with the Infotainment Package W/Bose Surround Sound System (option P9G) in 2017 and was still under the factory warranty. On the way home from purchasing the car I lost sound except for a faint muddled base sound. The next couple of days it was intermittent and I returned it to the dealer that diagnosed it as a bad PCM and after a long wait with out my new to me car, I got it back and had the same loss of sound on the way home☹️. I immediately took it back and they ended up replacing the Bose amp which is under the passenger seat. My car is a Cayman so a clogged drain and water was not the issue but still a bad amp. The Bose system has a separate amp for the subwoofer which is why I was still hearing a faint muddled sound from the subwoofer and no other legible sound. The Bose subwoofer amp is not under the seat but is above the passenger side fuse box under the dash and protected from water. Are you experiencing any muted sound from the subwoofer which is mounted above the steering column? I don’t know if I had any of the connection or other issues you are experiencing as I didn’t have the car long enough to connect my phone or try any of the functions before the replaced the amp.
Six years later and speaker upgrades, added backup camera and a proactive SSD clone drive everything is still working. And to confirm the Bose amp is located under the passenger seat and is prone to failure especially in Boxsters from water damage from clogged drains. I suspect/guess that your other issues are likely PCM related and as previously mentioned might be a problem with the HDD drive. There are some threads where a couple of members provide a service of sending a cloned SSD drive that fixes problems with rebooting and bad sectors on your HDD drive….might be worth a try if you suspect your HDD drive. I cloned mine while the old drive was still working with a SSD drive to avoid problems. Also it’s a good idea to update the firmware to the latest version V4.76 if you have an older version.
Jim

edit: Here is a link to a Planet9 thread where @ElCid86 has helped several by cloning his working HDD drive to a new SSD drive to repair others PCM3.1 with rebooting issues. It’s a long thread but mid way through to the end described the process.https://www.planet-9.com/threads/pcm...8/post-2138375
My signature on this Planet9 thread is 981cayman*s and I have several posts describing the cloning process I used on my working HDD to a new SSD drive.

JPPoulin

Hi Jim, thanks again for the interesting background story.

Here are more facts about my situation:
- All the symptoms in post #1 appeared all at once. I used to think that maybe a board inside the PCM went bad but now that you've shared your story and I learned about the audio-related circuit under the passenger seat.
- I don't know if my Boxster S 2013 has a module under the passenger seat yet. It will take me a couple of weeks to find out when I can return to the car.
- To my knowledge I don't have the Bose amp but the basic one. So no subwoofer amp so the sound cut completely.
- Given that some of the symptoms are not related to amp sound output I am not sure if a possible module under the passenger seat is at fault.
- My car took water and destroyed the rear control module under the driver seat. So if I have a board under the passenger seat it is likely it was damaged too and could explain my symptoms.

I didn't know the PCM had a SSD hard drive. Once I inspect the state of whatever board I have under the passenger seat, if I find nothing then I will evaluate if I can fix my symptoms via this hard drive repair process. I also didn't know the PCM firwmare was updateable so I'll have to research this too.

Thanks so much for all this new info... really helps! I hope the upcoming repairs will succeed and I'd love to hear what the lessons learned are!!

Jim981CS

I could be wrong but from your photo on your original post you appear to have the latest version of PCM3.1 which has NAVI and JUKEBOX and the later V4xx software version that can be upgraded to the final version V4.76. If you push the source and the info button at the same time it should display the software version and other information about the PCM including history of updates and even the Bose amp part number and SW version. Do you have speaker grills on the door speakers that say Bose?
Jim

_ - ← -, - -.. - - -, - -

JPPoulin

I am not sure if mine says Bose or not... I know my 2nd Boxster did but this one this newer one has less luxury options so am not sure. I'll be sure to check when I get back to the car in a couple weeks

Thanks so much for pulling these technical entries! I will also check the firmware version and see if upgrading changes anything. My top guess now however (after reading your situation) is that I do have a PCM-related board under the passenger seat and it is likely damaged..

More details when I can get back to the car

RobandyUK

I have the same issue with my PCM as the original post

worked great for years then sat nav stopped loading maps and rebooted itself every now and then
Decided to look at the hard drive so did a handover reset then cloned the drive
Put it back in and lost USB, Jukebox, Audio and mic on phone calls and now it reboots every 3 mins.
I checked the original HD to find it had loads of bad blocks on it, It looks like taking it out and trying to clone it just made a bad drive worse that i then managed to clone to another drive,
currently i have a working radio for 3 mins at at time with no other functions taht are fully working
Tried to do an upgrade with the latest disk 4.76 but it fails everytime on updating teh HD also
checked for water under the seats and its totaly dry as i would expect
Battery is good also
still working on tryig to get to the bottom of it but no luck yet

JPPoulin

Hi Roland, thanks for joining the chat.

Wow what a journey you've had. Thanks for sharing.

Perhaps replacing it with a used unit might be the best / cheapest way to move forward? Take a look at this eBay search and in particular units like this one for $430. Might get you further + faster to replace the whole thing? (I'm thinking of doing the same thing if replacing the module under the passenger seat doesn't fix my issues)

Alternatively for around $1100 you can find used PCM 4 radios that are in the one-gen-later Porsches. (I've seen how-tos on the procedure on eBay I believe). I hope these options help! Let us know how things work out!

Jim981CS

I recall that some have successfully used Becker in New Jersey for PCM repairs. I don’t know if that makes more sense than an eBay used unit but it may be worth checking out??? Also I mentioned in a post #23 above that @ElCid86 has helped some others by cloning his working HDD to a new SSD drive.
Jim

lagunatich

Update on my wet amp issue:

I took the 981 to a local shop specializing in Porsche / Mercedes / BMW audio systems. Diagnostics said the "rebuilt" amp was bad, not communicating with the PCM. Installed a new amp from Porsche (wholesale discount, thank you), and all is good. $1700, but could have been worse. Very happy with the shop: Rocco's in Costa Mesa CA.