PCM Help!

[Clutch-n-Throttle]

I just had my bonehead moment today.

A little background. I have a 2006 CS with Bose. I installed a mObridge/Cartronic BT/Ipod module for the PCM. It worked flawless for the past 3 years.

For the past 3 months, I have been having problems with the PCM. The radio/CD/mObridge would play and then cut out. The PCM screen would display "Loading CD...", the CD mechanism inside the PCM would run, and then the music will come back. If I was on a call thru the mObridge/BT, the "Loading CD.." would kick it and completely drop the BT function. I went to the Porsche Service and had them remove the CD changer from the MOST list as recommended by other mObridge installers.

A couple of weeks ago then PCM screen started to flicker and the PCM would go into a continuous reboot procedure. After some troubleshooting, I had to remove the CD mechanism inside the PCM for the system to work.

I thought I had solved the problem. Then it started again. I was noticing that mechanism for the CD changer in the rear would activate occasionally. I thought I had read somewhere that all connectors to the CD changer needed to be removed. I installed the loop on the CD changer fiberoptic connector.

Here's the bonehead move. I could not remove the other connector to the CD changer. It is a small connector with three wires; a brown, a yellow/orange and a white/orange. In a brilliant dumbass move, I decided to snip the wires. Well... Im up SCHIT creek. Now I lost the phone, amplified and NAV functions. I soldered the wires back and reconnected the whole system. I locked the car and let it sit for 15 mins. Still nothing.

Any suggestions? Does anyone know if there is a PCM/MOST ring fuse somewhere on the car?

I guess if I can't get this solved, I'll have to go the aftermarket stereo route. Not happy that I will have to drop $1K or more to get the stereo back.

Please advise.

PS: I know I'm idiot. Be gentle.

[Clutch-n-Throttle]

Uh.... Never mind. It was a blown 5A fuse in the passenger side fuse box. I think it was #9

I can't brain. I got the dumb! :)

Edited September 8, 2012 by Clutch-n-Throttle

[deilenberger]

Is it possible when you snipped the wires that they shorted together. The brown is ground (standard color on German vehicles..) I'd assume one of the other wires is switched power, and one is constant power (so you can eject a CD cartridge without having to power up everything.) If I had to guess - one of those circuits has a blown fuse.

Do you know how to use a voltmeter? That's where I'd start.. see what voltages under what conditions are on those two wires - measuring to ground.

[deilenberger]

Ah - you posted that as I was replying..

[Clutch-n-Throttle]

That's exactly what happened.

Still trying to figure out why the PCM cuts out and "loads" a CD. I removed the mObridge from the MOST ring and set everything back to the original config. The music would play from the FM tuner and after a few minutes it cuts out and "loads" a CD

I had to remove the CD mechanism from inside the PCM. Guess what? It still "loads" a CD. Don't know if it's a software issue inside the PCM or if the PCM is on its last legs.