I am new to this forum. So please be gentle with me. I did do a search, but came up empty in the 991 forum. I picked up my Aqua Blue CS Cab last week. I have 275miles on it now. After driving for 5min my PSM Failure message came on. I continued to drive in order to get home. 10 min later a second message stating my Auto Start/Stop is deactivated. I was not in Sport.

I parked, turned the care off then restarted the car. Both messages came back on the screen. I came back to car after being turned off and parked for 30 min, but the the messages persist. Obviously I will be bringing the care into the dealer, but I was wondering if anyone else has had this happen to them, and what it could mean.

I had a 2011 Panamara 4S and never had a problem with it (other then 4 flat tires) in the 13K miles I put on it.

 

Probably some sort of sensor issue. If it has to do with PSM, ABS, Auto Start/Stop then something in car doesn't know if the car is moving (one or more wheels) or stopped and you will start getting a bunch of messages from many systems.

Could also be some sort of voltage or voltage sensing issue as the Auto Start/Stop system does tax the electrical system a bit.

Most likely an easy fix for the dealer once hooked up to the diag computer and the codes read out.

Let us know the resolve...

 

The interesting thing is I starred the car back up 2-3hours later and the PSM failure message has now cleared off, but the Auto Start/Stop deactivated persists.

 

Almost the same thing happened to me a couple of weeks ago in my 991S. Turned out a wheel speed sensor had worked itself loose.

I was on the way to a wedding when the car went into limp mode on the highway. Was traveling about 80 mph and all of a sudden the car cut power and the speed dropped to about 40 mph and the car ran erratically. Got PSM/ABS failure, auto start/stop deactivated, parking brake failure plus a couple of more messages. The display lit up like a Christmas tree. Managed to limp into a service station close by.

Shut the car down and restarted it in hopes that it would clear the messages. Tried it several times. No dice. The I disconnected the battery and let it sit for about 15 minutes before reconnecting it and starting it again. Still no luck and 200 miles from my dealer.

To make a long story short, called Porsche Roadside Assistance and they flatbedded the car and me to my dealer. Since it was late Friday afternoon, the Porsche tech had left for the weekend and the earliest they could get to it was right away Monday morning.

In the meantime, the gave me a new Panamera to use for the rest of weekend and take back home until they could get my car fixed. Nice car. Put about 500 miles on it.

Dealer called me Monday morning with the fix and brought the car out me in the middle of week. They said the sensor was probably not attached correctly at the factory and worked it's way loose over the course of 4000 miles.

Anyway, the car runs great again and my thanks to Jerry and the guys at Valley Imports in Fargo for the excellent service.

Oh, and I did make it in plenty of time for the wedding.

 

I had a PASM failure warning. Turned car off then back on. Camed back a couple of times. Took it in and they not figured out what it was but it has not come back.

M

 

So after 2 days at the dealer they tell me there is a problem with a brake switch. Apparently the brakes are fine, but the sensor was not working causing the failures. In addition to the PSM and Auto start/stop it turns out that the Cruise control was also not working. The part is on order and should be here this week.

 

It all makes sense though, if the system does not know when the brakes are applied many things won't work. Including PSM, auto start/stop & cruise control. Just a pretty simple and not too expensive little part that when gone wrong causes major havoc. Once fixed, should only be a distant memory.

 

HoleDgr: is your car 2012 or 2013 model year?

 

2012

 

Same happend to me - PSM Failure & Start/Stop switch deactivated - brought it to dealer - no logs- hasn't happened since

 

yes just happened to me this afternoon; both psm and auto start/stop deactivated. the trouble went away then came back again this evening. the engine felt abit weird but got home safely. anyway, will bring it into the dealer next week.

 

PASM warning a week ago, now cruise control does not work. Noticed Auto stop was randomly not working for several months. Dealer says need to order a part and that brake lights may stay on ?? Still sounds good anyway-except the Bose buzzzzz

 

This pair of warning flags have cursed my '13 C2S for years. Of course, the dealership has no clue. As if they've never seen this issue before. But they happily replaced my battery, being the "probable culprit." Nope. They still come--as has been said, and they go. I top off the battery routinely. Still, they come back, or not.

I love my 911, but this does suck. And it really puts me off the dealership. They've never heard of the problem before? Really? Just google the pair of warning messages. All Porsche models appear to subject to this.

Porsche needs to rework it's software and/or sending-unit network in its cars. These spurious messages, that don't lead to the identity of the specific problem, as admitted by the Porsche techs, have to stop. The dealership, at least, needs to know how to interpret these warnings and the problem they indicate.

But where's the money in that...right?

 

I also experienced this on a 991.1. After replacing the battery, it never came back. Good luck

 

Thanks, I'll meet it. They put in a new battery ($$$), and no improvement, no change.