Dennis C

I've had two instances over the last couple of years of this happening. I start the car, and I get no sound, as you described. In both cases, the system worked properly after I shut the engine off and restarted the car.

ltc

The DSP initializiation "feature" is simply a timing event that happens very infrequently on startup.
It seldom happens 2x in a row.

If the amplifier is exhibiting a 'no audio' condition consistently, I do not believe it is the aforementioned issue, rather something else.

Sam CS 05

FWIW, my CDR23 used to freeze on Porsche logo and not respond and no sound until the dealer replaced the head unit under warranty. No problems since.
GL
Sam

alsamrob

When I removed the fuse, there was an audible "thump", similar to when you hook speakers up to an amp that is turned on, but there is no source playing through the amp. Could it be a connection from the HU to amp came loose? I know I am grasping, but would like to have some chance of success before I dedicate a weekend to tearing apart the dash.

I am guessing that the "something else" will likely require dealer diagnosis.

porsche52

There was a ATI (advanced technical bullitin) that might apply to you situation. The fiber optic (MOST) lead at the back of the CDR 23 or PCM was wrapped to tight in the main harness loom causing it to be pulled to one side, thus causing a intermittant connection (no sound). We were instructed to cut out the fiber optic loom from the main harnness to free up the cable. You may try this, might fix it, might not. The MOST system is a fiber optic ring, if one component fails, the hole bus fails. Therfore if the Amp or any component for that matter can be optically ok but electrically faulty, causing the bus to fail. My guess is the Amp is electrically faulty, seen this alot.(located in the right rear corner, above the CD changer if equipped, you can sorta see it through the little access panel in the rear cargo trim panel) The IPOD could be an issue as well if it is tapped into the fiber optic bus, or is it FM modulated? If you do take it to your dealer, have them run a MOST ring test via the PIWIS tester. It will perform a self diagnostic test on the MOST system and condem a failed component if that is the case. The ATI above is a DYI job. The other stuff, not so much. Keep us updated

ltc

^ + 1
Very well said.
Would you like me to autograph that ATI on behalf of Larry?
Never know, might be worth something someday....or maybe not.

alsamrob

Thanks for the info. The Ipod is connected to the MOST ring through mObridge. I can access the ipod, and even change tracks on the HU, but no sound. I have tried the fuse removal, with the ipod connected and without it connected. Does that mean anything with respect to the integrity of the bus?

I'll try option one, and if that fails schedule the visit to the dealer.

mudman2

Amp

ltc

That hurts.

mudman2

The truth does sometimes just ask Mr CEO, PAG

racer_65

I've had this happen a couple of times on my '06, and then it fixed itself. Therefore, it's not just a "Beta" problem.

alsamrob

Amp, as in get a new one?

mudman2

Most likely, or maybe a firmware update from PIWIS is my bet

alsamrob

Update: Brought the pig into local Porsche dealer to determine if it is in fact the amp, or SW/HW etc. They are telling me that they could not access the control modules of the vehicle to read any faults. They said they could not communicate with the car at all. Thought it might be the mObridge unit. This happened before as well when they had to enable CDC so I could install the mObridge.
My question is: is that even possible? the mObridge worked fine for 9 months, and the HU controls the Ipod fine when hooked up. Could the mObridge be blocking the communciation with the car, but be working fine in all other respects? Arrrggghh.

mudman2

Just pull the fuse on the mobridge, I had a similar problem with the goons at my dealer. Now I do that everytime I take it in