alexb76

cosm3os

Believe it or not--normal.

bmwfan328

fast1

Same here.
Was the battery replaced by a Porsche dealer and underwent the initialization process? Some owners have reported bizarre issues after just doing a battery swap themselves.

daddyscar

nosnow

Mine does the samething. If the car is in a parking garage for the day the clock wont fix itself until I leave the garage. Took me a coupke time of resetting the clock to figure it out.

Petza914

If your car has nav, the clock will stay accurate because it gets the time info from the GPS satellites. If you don't have nav, the clock will lose time, maybe a minute or 2 per month, but losing hours in an afternoon is not the normal behavior.

When I notice mine is slow by a couple minutes, I reset it 2 or 3 minutes fast and then I'm good for a few months.

NuttyProfessor

First world problems.

alexb76

I changed the battery myself, so not sure if I had to do anything for initialization process?

I figured out what's going on though... when I FIRST start the car, the CLOCK in the DASH is CORRECT... it's exactly what I set it to, BUT, the PCM (with NAV) clock is reset to 12:00, when I start, it changes the dash clock to 12:00, BUT then SOMEHOW in a few mins, it corrects itself?! WTF! I went into PCM and changed clock to be exactly what it was on the dash and they're synced somehow, so not sure how the heck the two are not in sync always... any other ideas?

Fahrer

I could be that the clocks in these cars are radio clocks. There are apparently not many radio transmissions in the US for radio clocks. When I lived in Germany all of my clocks at home ( and in my car?) were receiving radio messages from a source in Hesse. These signals are based on an extremely accurate clock and are constantly broadcasting the actual time to these "funkuhrs". Of course if we don't have a widespread time transmission in in the US these otherwise inaccurate clocks will not be constantly updated. I am not sure if that is the reason for the issue. The cars with nav, of course,have a different sat based system.

Brainz

There's many reports of this behavior occurring lately. Mine does it too. Weird.

I recently cleaned the rotating connector for battery positive power at the forward firewall. It seemed to have some corrosion/dust - - am wondering if that's related. Will know in a week or two...

wc11

Clock ?

Matt(inMA)

My '06 has done this from new - The first winter I stored my car I realized the clock was still accurate when spring arrived. So this really puzzled me. I kept an eye on my usage and the clock (I know, I need a life) and found that every so often when I started the car the clock would move backwards 1 minute - but not always. I don't have nav. It would be interesting of any of you that have this "feature" if you find it more frequently when using your cars vs storing them.

YMMV

Matt

Brainz

So far, my hope that cleaning the positive battery terminal would make my clock behave has been a failure. The clock is still randomly changing time.

I still suspect it may be voltage related though, but that's just a hunch.

Weird bug. Somewhat comforting that [many of them] do that...

Brainz

It's been 5 more weeks and I wanted to follow up and report that cleaning the positive battery terminal has in fact seemed to have fixed this clock reset issue and also the slow crank when hot issue. Note that I have a 997TT which is NOT known for the starter cable/slow crank issue that affects the non-turbo 997s. That said, I suspect ALL the 997s may benefit from this fix.

As previously posted by another Rennlister (all credit to him/her), the positive battery cable in the frunk is connected to some sort of voltage distribution module that passes through the firewall. Rather than using a solid/bolted connection, the cable that connects the positive terminal on the battery to the car uses a connection the actually swivels on a post on the firewall- - you'd never know it unless you got in there and looked close and/or wiggled it as it's hidden behind a large wiring harness.

Inside this swiveling connection are a bunch of brass/copper "fingers" that are slightly spring-loaded and pass the voltage to the post in the center. It appears this connection can get oxidized and may limit the amount of current/voltage that the battery can pass to all the electronics in the car. This would explain the issues experienced.

To fix it, pull the red (looks orange in some pictures) latch on the connector down/away from the pivot point and wiggle the connector off the post. I then used a .357 /9mm brass bore brush to gently scrub the inside of the connector and also some 0000 steel wool inside a socket to polish the post - - don't be too aggressive with the fingers on the connector side, you don't want to damage them - - my bore brush spun easily in one direction, but not the other - - I didn't force it as I didn’t want to mess up the fingers. I also painted a tiny amount some Deoxit terminal cleaner on both sides of the connection and reassembled. It's been working great and my chronic clock reset issue is solved.

Here's some pictures - - I removed the battery for more space and to clean up the tray, but you could likely do this with the battery in place. Takes 15 minutes.