PCM is possessed!

[PeterMiller]

Hi guys,

I have a MY05 Cayenne S in the UK and the PCM (v2) is starting to show some rather weird and random behaviour.

I have the multifunction steering wheel, and most of the time, it's only possible to adjust the volume using the controls on the wheel. The PCM control knob doesn't function. Sometimes it does, and then it blairs out. I've removed the knob and checked for dust / grime, but it still plays up.

Other times, when the audio is in 'mute' via the steering wheel control, it will randomly come out of mute into the last volume setting whilst driving along. This is very distracting.

I've performed a factory reset via the menu system, but I think that this only resets the audio customisations. It feels to me like it needs a full reset.

Is there any process that I can follow to force a hardware reset of the system? Any other ideas gratefully received.

Cheers

Pete

[odix]

Hi -- There is a more detailed system reset here in the posts. I forget the details but it involves the key and other steps. If you search I think you can find it.

Also, for overall electric and PCM problems a new battery(s) may be in order.

[PeterMiller]

Hi -- There is a more detailed system reset here in the posts. I forget the details but it involves the key and other steps. If you search I think you can find it.

Also, for overall electric and PCM problems a new battery(s) may be in order.

Thanks - I did try a search, but will try a wider search term. If anyone has any more info, please let me know.

The wife has just come back from the school run and reported that the PCM asked her 13x times whether she wanted to make an emergency call. Very strange.

[PeterMiller]

OK, I found something that has restored my volume control. I'll need to take the can for a run to check other things.

A reboot of the PCM system was performed by

1. entering the car;
   
2. no keys in the ignitiion;
   
3. shut the door;
   
4. the PCM could be heard to start up;
   
5. Press & hold 1,4,8 on the keypad - the Porsche logo will come up - keep holding - then it will go off.
   
6. power on the unit and the logo will come back on.
   
7. you should still have your presets etc, but for me, hey presto, the volume now works.
   

Hope this helps someone else. Now... off to contritbute... :)

[PeterMiller]

Hmmm... That didn't last long.

The 1,4,8, trick works ocassionally. The gremlins come and go.

Could this be related to the fact that my alarm siren is very low in volume (barely audible)? The rear wash wipe pipe has popped off the nozzle jet, so it may be possible that water has got in the back compartment. Are there any PCM related electronics in there? (BOSE premium package).

[mudman2]

Peter

I have had an 04 from new, basically the same equipment as you. The Bose amp was a problem in the 04-06 MY and in a lot of cases was replaced under warranty. I have had misc no sound issues over the years, always solved by one or more cold boots. i.e. removed key from car, wait 5 minutes and then try again, that gives the system time to go back to sleep completely.

I would say I get the problem every 6 months or so, never more often than that and it takes 1 or up to 4 reboots to get it back up. When it was under warranty I would take it to the dealer and got the NFF response everytime.

As I said there are terminal issues also with the Bose where it just dies, if you cannot get it back on after reboots then its either the amp is dead or one of the fibre cables has worked its way loose (rare)

[bleo]

I would recommend to you to check wires and connector contacts and switches (can be damaged or corroded) used for PCM remote control on steering wheel. Maybe it could help. BTW, what happens with PCM unit when you just simply disconnect this feature? Does it work normally?

Hi guys,

I have a MY05 Cayenne S in the UK and the PCM (v2) is starting to show some rather weird and random behaviour.

I have the multifunction steering wheel, and most of the time, it's only possible to adjust the volume using the controls on the wheel. The PCM control knob doesn't function. Sometimes it does, and then it blairs out. I've removed the knob and checked for dust / grime, but it still plays up.

Other times, when the audio is in 'mute' via the steering wheel control, it will randomly come out of mute into the last volume setting whilst driving along. This is very distracting.

I've performed a factory reset via the menu system, but I think that this only resets the audio customisations. It feels to me like it needs a full reset.

Is there any process that I can follow to force a hardware reset of the system? Any other ideas gratefully received.

Cheers

Pete

Edited January 25, 2011 by bleo

[IH8-V8]

I lost my steering wheel controls (Radio and Tiptronic) a few months back, and now the radio is acting strange. Screen goes blank, controls on the radio don't work, etc.... I turn off the car, and the radio is illuminated and won't turn off. I have to pull the fuse to get the thing to shut down. Freaking frustrating nightmare. I have been searching the Globe for an aftermarket radio option. I hate the Nav on my 04 Cayenne Turbo, and I can't stand that I can't use MP3 discs or My iphone. Id prefer an aftermarket radio at this point... But I can't find ANYONE who has successfully swapped one out.

Can you guys recommend any threads that might help me find an aftermarket wiring harness for an aftermarket radio?

Any advice on the steering wheel controls - I have checked for loose wires - and it seems to be a freaking gremlin?

[mudman2]

I think its already been said here but at the first sign of trouble and your 04/05/06 think battery. It can get very wierd, I would rather they put a sign on the screen that says CHANGE THE bleeping BATTERY