Dash lights going crazy, car may be possessed...

[JHop]

Hi to everyone, newish owner, new poster...

My C2 has been acting strange for a few weeks...all dash lights are coming on at random when car is just sitting (no key in it) along with System Fault, Spoiler Control Failure, Oil Level Sensor Failure cycling through the info window...start car, all is normal, everything works as intended, no faults. Sometimes it just goes away on its own.

I have replaced the front control module and the battery, will test charging system and battery cable next. Anyone seen this before? Started acting weird when we got a hot spell here in Portland. Alternator maybe? Car has about 87k on her.

Any insight appreciated.

JHop

[Ahsai]

What's the voltmeter in the instrument cluster reading when you're driving the car (should read between 13.5V and 14.5V) Any aftermarket electronics that may drain the battery when car is sitting?

Edited August 18, 2014 by Ahsai

[JHop]

No voltmeter in cluster on my '06... Took reading of 13.6 at battery while idling.

No aftermarket anything on car. Bone stock. Had some TPMS issues, but new sensors solved it.

[Mijostyn]

Hi JHop,

It is not the battery or alternator. You most likely have a communications problem. Everything talks to everything through what Porsche calls a gateway module. This is done over a fiber optic bus system. When my 06 C4S went fruit loops it turned out to be a faulty PCM module. But the mechanic replaced the gateway module, the PASM computer and my instrument cluster before he finally figured it out.

If the car runs and everything works as advertised when the car is on I would just hang back, drive the car and see how things develop.

Hopefully at some point things will get bad enough that the problem will be easy to diagnose wasting less time and money. The car has default modes so it is not likely to leave you stranded although my car was stuck in track mode which made daily driving a bit rough. You will certainly need a tech with a PIWIS computer. You will be lost on your own. Just swapping parts out is a very expensive way to go with these cars.

[JHop]

Mijostyn,

Thanks for the feedback! Yes, I'm trying to avoid more of the part replacement route...the control module was the first thing that was "diagnosed" from the dealer...

The car drives just fine, now it's just doing the wait and see and eliminate variables...

[RFM]

Mijostyn's post made a good point regarding the use of PIWIS, only the explanation regarding the communication between the control boxes/gateway via fiber optic cable is not entirely correct, he probably meant canbus, fiber optic is associated with audio.

[JHop]

All this computer stuff just makes me yearn for my '85 Targa.

Much more simple. But hey at least the AC works on the 997! :)

[Phil_D]

Just a thought, but did you get the front control module programmed correctly?  

 

I had a faulty front control module (after polishing the headlights) that threw all sorts of codes and messages.  I replaced it with a new one and it was even worse than before, as the module needed to be programmed for my vehicle.  I tried doing this with Durametric Pro and it still caused problems.  In the end I put the original module back in, cleared all the codes, and it's been fine ever since.

[JHop]

Had a new FCM put in and programmed at the dealer. Also had all codes cleared, etc. Some instrument cluster communication fault codes showed up (and one about the driver door?!?) but the car has been behaving normally for the past week or so. Go figure. We will see what happens...