CBR786

hi I need some advice my PCM 2 has died well the screen and the CD disc is not ejecting from the PCM. When I pull it out and look at the rear of the unit the red optical signal is emitting from the PCM out bound but the head unit is dead otherwise as no sound no screen light up and no disc eject. The cd changer in the boot seems to work fine as the discs magazine ejects fine and goes in fine.

The issue is I can send unit off to some electronics shop to repair it or swap out with another PCM 2 from a breaker if I swap out with another PCM 2 I hear conflicting advice some people say it will plug and play others say I will need the original VIN from the donar car of replacement PCM2 to obtain a code ? The serial number will not generate a code apparently ?

I had an issue with the PCM first as it developed a fault of no sound so I assumed the CD changer or the amp or phone module was faulty for no sound issue but then before I could look at what was causing the no sound the PCM went dead ?

now I have to get the PCM working again so I can diagnose where the optical fault is that is causing no sound ?


any contributions from any one with knowledge of this area would be most appreciated.

dan_189

You'd need to reprogram the car to work with a new PCM2 unit based on my reading of POSES.

Not sure who fixes PCM2 units over in the UK perhaps get in touch with Becker directly - they are the PCM2 manufacturers - they are still just electronic components.

FYI:
https://rennlist.com/forums/964-foru...repair-uk.html

CBR786

Thank you for the input Dan, I gave the head unit to a electronics shop to see if they can spot anything obvious they opened the unit and said it all looks good and no issues. They could not power it up as they say it is operated by CAN BUS system and the CAN BUS ultimately sends a power signal to make it switch on. The shop mentioned my system is working and the fault is in my car somewhere which is causing the head unit not to power up?

I have luckily got hold of another PCM 2 unit and will try that in the car if this does not power up then the fault 100% is with the CANBUS system. I know my AMP might be faulty I am thinking a faulty AMP might in turn cause the Head Unit not to power up possibly ?

I will double check the fuses in the footwell and the one in the rear of the head unit are there any other fuses that I might need to check?

dan_189

Fuses and also the alarm system fairly sure the head unit is wired into that and the DME. Would be handy to have it scanned with a diagnostic tool as well (the car).

CBR786

the shop I used where a bunch of idiots. They told me the system powers up via CANBUS but when I checked the wiring loom in the car I could not see a CANBUS (two wires intertwined) on the loom. I managed to power up the second PCM on the bench and although I can not test the sound as I just wanted to see it power up it works with one earth connection and two lives one being permanent and the other Ignition live. I will use the spare PCM I have to diagnose if the the Amp or CD changer/ Phone module has failed that is causing mo sound. I ordered a MOST optical connection loop to help me diagnose components.

Imo000

I have acronyms. What's PCM2?

dan_189

Porsche communication management