[Designer]

So, get in 955S and it starts and sounds normal.
Speedometer immediately goes up to 93mph on both gauges. Fault codes all over (CEL, ABS, brake proportioning valve, refuel now (tank is full), PSM, etc.). Drives normally. Battery less than 3 years old.
At dealer now. They did 1 hour diagnostic (@ 230/hr) and have no clue. Gauge cluster checks out. Of course, more diagnostic hours are needed to determine the cause.
  
Anybody have an idea?

[fpena944]

So, get in 955S and it starts and sounds normal.
Speedometer immediately goes up to 93mph on both gauges. Fault codes all over (CEL, ABS, brake proportioning valve, refuel now (tank is full), PSM, etc.). Drives normally. Battery less than 3 years old.
At dealer now. They did 1 hour diagnostic (@ 230/hr) and have no clue. Gauge cluster checks out. Of course, more diagnostic hours are needed to determine the cause.
  
Anybody have an idea?

I believe on the 958 there is a setting where you can set up a speed alarm. Is that the case on yours? If so can you reset that and see if it makes a difference?

I've never heard of anything like this. So once in drive does it go back to 0 MPH and then accurately reflect speed once underway?

[N_Jay]

Have them give you a list of all the codes they found.

Then have them clear the codes and see what comes back.

[XR4Tim]

The only similar thing I came across on a 955 was an incorrect fuel gauge reading. I don't remember what the gauge showed, but it always read the same, regardless of how much fuel was in it.
Unplugging the cluster and plugging it back in actually cured it.

[Designer]

Thanks for the suggestions, Guys.

After repeated starts and short drives, speedometer calmed down and some alerts went away. Still shows CEL and Refuel. Dealer checked fuel system and looked for water damage and tested wiring. Tomorrow they'll look at the gauge cluster again.

[N_Jay]

Did they get you the codes?

[Designer]

Dealer had the car for a week and tested everything:


Upon return, had a few small issues that then went away. Started it the other day and speedometer went up to 60 with a few warnings. Clicked my seatbelt to turn off the chimes and it went nuts. Every light possible lit up and speedometers went right to 185! Move over Joe Walsh.

In today for a new $3700. gauge cluster.

[tooloud10]

Battery less than 3 years old.

Man, I would hope that they checked this. I've never had a Porsche SUV but a 3-year-old battery is about two years too old on my BMW and I can always tell when it needs to be replaced because every light on the dash gets wonky out of nowhere exactly like you describe.

On the V8 E70 they actually started recommending a new battery at every oil change.

[fpena944]

Dealer had the car for a week and tested everything:


Upon return, had a few small issues that then went away. Started it the other day and speedometer went up to 60 with a few warnings. Clicked my seatbelt to turn off the chimes and it went nuts. Every light possible lit up and speedometers went right to 185! Move over Joe Walsh.

In today for a new $3700. gauge cluster.

Can't do a used cluster for cheaper?

[Designer]

Can't do a used cluster for cheaper?

Yes, they're on Ebay. I'm biting the bullet on this because the car is in such great condition. We've had it for 15 years and plan on keeping it until it literally falls apart. 101k, black Titanium S with nice, additional options. That, and peace of mind/happy wife. She drives it the most and is in love with it.

[fpena944]

Can't do a used cluster for cheaper?

Yes, they're on Ebay. I'm biting the bullet on this because the car is in such great condition. We've had it for 15 years and plan on keeping it until it literally falls apart. 101k, black Titanium S with nice, additional options. That, and peace of mind/happy wife. She drives it the most and is in love with it.

I know the feeling. We love our CTT also although we have considered getting one of the next-gens instead but the price is outrageous and I could pretty much rebuild ours at a much lower cost.

Post some pics when you get a chance, always like to see a good condition Cayenne.

[Designer]

Well whaddaya know?
Props to the dealership (Lehigh Valley) for their perseverance. Throwing parts at a problem is never a good idea.

img920.jpg

_DSC0249.jpg

[fpena944]

Well whaddaya know?
Props to the dealership (Lehigh Valley) for their perseverance. Throwing parts at a problem is never a good idea.

img920.jpg_DSC0249.jpg

Gorgeous vehicle!

Wow a shop that actually diagnoses problems instead of just replacing parts...what a concept!

Sad part is if you could have replaced the entire dashboard and still ended up with the same issue all because of wiring.

I'm sure you are quite relieved to be back to normal again.

[i am not a traitor]

Well whaddaya know?
Props to the dealership (Lehigh Valley) for their perseverance. Throwing parts at a problem is never a good idea.

img920.jpg_DSC0249.jpg

Excellent outcome considering the alternative. Too bad it took so long. Also, I didn't realize that you were also in PA!

[Designer]

Also, I didn't realize that you were also in PA!

If you ain't Dutch,
you ain't much.

[Designer]

the saga continues.
when this all started, i suspected the battery based on tos in the old days when the mantra was that most electrical funny stuff was traced to the battery. so new battery. a few months later, the battery was dead and had to be towed. they charged it and said everything is fine. that's when the funny stuff really started-see above-. so wife and i said as long as everything calms down once you drive it-we can live with this.

whenever we had car in for inspection/oil change -- yes, i could use an indy for much cheaper, but they're close by, and unlike an indy, we get a loaner. usually a new, base macan or cayenne--we told them it was still f-cked. so they decided it was a dirty wheel speed sensor. they cleaned it and declared all good. nope. then they replaced said wheel sensor-pelican calls it an abs sensor. nope.

then it got serious. wife was in a head-on parking space, engaged reverse and engine revved, but would not move. luckily she had space to pull forward a bit and then reverse engaged. took it back and said FIX THIS!

lo and behold, it happened for them! well, now things were different.
they installed a new battery and said just drive it, we'll worry about the bill later. he DID originally offer free diagnostics.

not a problem since.
so i intend to tell them we're even. the original charges to "fix it" and years of aggravation, having a mechanic driving it home and back putting 250 mi on it- after telling them it only happened on start-up- and a bad battery at the beginning, pays for the new battery. been going there for 16 years -different owner now. we'll see.