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The PCM on my 2014 Cayenne has stopped working. The screen shows the Porsche logo for a few seconds, then goes blank, then cycles back to the Porsche logo...and keeps doing this. There's a whirring/clicking sound you can hear as it cycles. The backup camera does still work on the PCM/screen when the car is put in reverse; otherwise there's just the blank screen with the logo cycling on and off. I have hooked up a code reader to the car: no codes. I've also taken out the fuse for the PCM: no change when I put the fuse back in. Questions:
1) What is the likely problem?
2) Anything else I can do to diagnose it?
3) What's the likely fix?
4) Is the fix something I can perhaps do myself or is this realistically a dealership trip? How big a job is is this in terms of parts cost/labor?
Thanks for any input!
I'm no expert on this, but sounds like a boot up problem. Wonder if there's a harddrive inside that has failed? If there's one in there and it's a standard spindle drive, would explain the clicking.
After reading about all sort of modules in this car and how they are programmed to interact with the car. I bet this requires the dealer.
Again, IF it's a drive gone bad.. there's a way to recover a drive. Using a company that disassembles them and gets data out. Then put all that on a new drive and try power it up again.
I've used Fields Data Recover in past. We've had drives and USB thumbs recovered in past. But they destroy the drive in the process. So as long as it's not on an eprom maybe you can get it done.
If you aren't under warranty the dealer solution will likely be very expensive. You might try calling Becker Auto Sound as they make/repair the PCM units and may have some suggestions as to what the issue is. If you need to send it in for repair it'll still be a lot less than the dealer would charge to replace it.
Remove the rear panels and unplug the amp harness for a few minutes. Then plug it back in and turn the radio on.
You may also be able to perform this functionary unplugging the battery for a bit but I weighed out the work on each and decided the not having to remove the seat was an easier task for me. Also I can't guarantee the battery being unplugged is going to work. heck I can't even guarantee that the amp harness unplug will work either but it did for me a few weeks back. Go look for my thread.
Remove the rear panels and unplug the amp harness for a few minutes. Then plug it back in and turn the radio on.
You may also be able to perform this functionary unplugging the battery for a bit but I weighed out the work on each and decided the not having to remove the seat was an easier task for me. Also I can't guarantee the battery being unplugged is going to work. heck I can't even guarantee that the amp harness unplug will work either but it did for me a few weeks back. Go look for my thread.
It's not necessary to remove the seat to disconnect the battery. The ONLY ground from the battery goes to the floor of the chassis on the drivers side right in front of the seat pedestal. There is a flap in the carpet to get to it. You can easily access it - then simply remove the acorn nut holding the negative lug to the chassis - and the lug from the stud welded to the chassis - and the battery is disconnected. Takes about 2 minutes. WAY easier than any other way, especially removing those damn rear panels..
Definitely give Becker a call. When I had my PCM repaired it was $800 but that was much cheaper than a replacement unit and came with a 1 year warranty.
Wouldn't unplugging the amp harness or disconnecting the battery do the same thing as removing the PCM fuse? I've already pulled the fuse and it didn't help. If there's a reason to also try the battery disconnect I will do that but I'm thinking it's the same thing?
Wouldn't unplugging the amp harness or disconnecting the battery do the same thing as removing the PCM fuse? I've already pulled the fuse and it didn't help. If there's a reason to also try the battery disconnect I will do that but I'm thinking it's the same thing?
There is undoubtedly more than one fuse powering the PCM.. so if you only removed one you haven't completely removed power. Disconnecting the battery ground will do that.
Was the nut lose when you tried to remove it? If so, you may have a stripped nut or bolt/stud. Or, when you tried to remove the nut, the nut or bolt/stud was already stripped. Also, if the nut is lose then you may have a grounding problem that may affect other components. Just ask Porsche 928 owners how important grounds are.
The PCM on my 2014 Cayenne has stopped working. The screen shows the Porsche logo for a few seconds, then goes blank, then cycles back to the Porsche logo...and keeps doing this. There's a whirring/clicking sound you can hear as it cycles. The backup camera does still work on the PCM/screen when the car is put in reverse; otherwise there's just the blank screen with the logo cycling on and off. I have hooked up a code reader to the car: no codes. I've also taken out the fuse for the PCM: no change when I put the fuse back in. Questions:
1) What is the likely problem?
2) Anything else I can do to diagnose it?
3) What's the likely fix?
4) Is the fix something I can perhaps do myself or is this realistically a dealership trip? How big a job is is this in terms of parts cost/labor?
Thanks for any input!
Hi, the same problem happened to me today. PCM in my 2014 911 failing exactly same way you describe above. How did you end up fixing it?
Hi all! I had the same rebooting issue, so I called our Porsche dealership her in New Orleans. They emailed me these instructions on how to reset the PCM and explained that XM had made a change that affected Porsche’s. Worked like a charm after sweating some bullets that we were about to have to shell out some serious cash.
02-13-2019, 04:56 PM
PCM not working
