PCM2 showing wrong date

[minny]

The date on my 2004 996 turbo PCM2 is wrong and i cannot correct it even with a PIWIS or PST 2. The problem started about a year ago when the date would sometimes not show when the unit was on and would either appear later or if I pushed the 1, 4 and 8 buttons together to soft reset the system. The problem then recurred when I re-started the car later.

However, over the last 2 months, this is no longer an issue in that the date is showing all the time as it should except it started on 01/01/2000. I am now on 26/02/2000 and I used the PIWIS and PST 2 to try to code the date in the MMI module but it didn't even change. When I did it in the Navigation module, it corrects on the screen for 10 seconds then reverts to the pre-corrected date.

Any advice would really be appreciated if anyone else has had the same problem and how to correct it.

 

[Richard_Hamilton]

Lots of reports of this on PCM2.1 (9x7 cars). One possibility is the GPS "Millennium Bug" desribed here: https://thenextweb.com/te...-problem-of-their-own/

 

[minny]

Thank you. On other forums, there are reports that trying to recode the PCM by parking the car in a garage then leaving unlocked overnight may work as the car cannot receive a GPS signal and somehow the new date sticks. I may try it at some point when I get round to it.

 

[Steve_996_4S]

I have exactly the same problem. I was told to leave the car unlocked, engine off but ignition on for a couple of hours in an open space. Was told that PCM2 will reset to current date once it has received new data from the GPS satellites. Tried this on my driveway, with car blocked in for security, but did not work.
I will try the suggestion to leave it in my garage unlocked overnight and see if that works.

 

[mbaxterjones]

I have the same issue with my car. Left it unlocked in the garage and that hasn’t helped, any other advice would be appreciated []

 

[minny]

From what I can glean from others' success, it seems to work if you have coded the PCM with the PIWIS or PST2 while the car is hidden from the GPS signal e.g in a garage and leaving the car unlocked for a day or two. I don't think just leaving it unlocked in the garage would work.

 

[wibble]

This sounds like a firmware issue or a standby battery fault on the PCM (common fault on old computer devices). Most units that have a memory will require a standby battery (e.g. LR44) to keep it active in the event main power is lost, such as a car battery in this case. If either loses power then the memory will erase and default to factory settings. A remote key fob would be another example.

I suspect a similar issue is being experienced here. Without taking PCM apart it is difficult to diagnose without seeing the circuit, but pretty sure one of our US cousins on rennlist will have done it. The millennium bug is firmware and would require memory to be flashed to the latest version - I would have thought this would have been a routine fix during a service? Being proprietary units this may prove to be difficult to fix without cooperation from the manufacturer or those in the know.

 

[D911ARK]

Weirdly, I was coming on here asking how to set the date, as mine has been incorrect for a while now, and thought I'd done something. It's not a big issue, but it is bloody annoying, as now all I see is the year 2000, and how I wish I was 19 years younger

 

[minny]

I tried coding the car in the garage so that it wouldn't pick up a GPS signal but have been unsuccessful. I can change the date on the PIWIS and the car momentarily accepts it then revers to 02.02.2000. Guess I'll just have to live with it. Annoying but its a first world problem really.

 

[Jon_Dakeyne]

A quick follow up with this thread as mine has been doing the 'old date thing' for a few months now and I've just lived with it, but now the clock is showing slow when the car is left and then as soon as you put the ignition on it shows the correct time. Must be a back-up battery failing or failed thing, but I would have thought it would stop altogether and re-set to 0:00 or 12:00. Anyhow just thought I'd put it out there. When I have time I'll pull out the PCM and look for a battery.

 

[D911ARK]

Did anyone successfully solve this or find a root cause?

 

[minny]

No joy so far. It is basically a software issue as described in the link that Richard attached above. Unfortunately our cars are too old for Porsche to issue a fix. Mine now says 02/07/2000.

 

[Mattjevans]

Rip it out and put in a modern CarPlay double din unit. PCM was bad when it was new, it’s terrible now

 

[Patenaude]

My date has been blank on the main screen for months and on the programming page it is stuck on 01/01/2000. I went to the dealership for a Nav update and a problem with my radio having no sound. I also asked the tech if he could set set the date so it shows on the main screen. He did the Nav update as well as set the correct date however he said he didn’t have much faith the date would stay. Not much luck with the radio issue either but at least for three days I enjoyed the correct date showing on the main screen however I pulled and re connected the PCM fuse to see if I could get sound out of my radio (which I successfully did temporarily) however the date disappeared again. Both issues are driving me nuts!