Iceter

"Convertible top not in limit position"

We know that this is an issue on 997 cabs, and I've had sporadic issues with this message popping up when I put my top down. The top works fine but when down, the message would occasionally pop up. Until now, it's been easy to clear by partially raising my top and putting it back down.

Suddenly, however, the damned beeping and message flashing on the dash are occurring every time the top is down and it's driving me crazy. Fiddling with the top button doesn't clear it any more.

Before I take it in to the shop (my dealer is not close by), has anyone figured out what causes this message and is there a quick fix?

Iceter

82 views and no responses. I'm going to take that as a "no".

Caughtacab911

OK, I was one of those people who read your post and didn't respond. Wasn't sure you'd want to hear what I had to say

Seriously, my 2005 997S cab (sold last year) had this problem intermittently and I took it to the dealer several times. They were never able to trace a fault code or solve it. The suspicion was a faulty contact somewhere, tough to troubleshoot apparently. It would happen only when the top was down and I was driving, more often than not when I hit a bump. It would come on and beep annoyingly as you know. Finally (like you) I'd have to pull over and stop, start closing the roof, then reverse the process and re-seat the top. That would usually work. Sounds like yours is happening much more frequently. If so, a dealer should be able to figure it out.

Hope that helps.

Iceter

I guess I'll start with cleaning and lubing all of the automated latches. I see three right off the bat--one on each side and a larger one in the center rear. Thinking as logically as I can manage, I believe this has to be some switch that senses when the rear deck is latched down tightly so either the latches aren't fully actuating or the switch doesn't think that they are.

stronbl

I would be inclined to work on the electrical side given what you note happens.

There are several switches, a couple potentiometers, and a main control unit.



1 - Rocker switch
2 - Display in on-board computer
3 - Microswitch, latching hook (windscreen frame)
4 - Microswitch, convertible-top lock (convertible-top side)
5 - Potentiometer, convertible-top interrogation
6 - Control unit
7 - Microswitch for convertible-top compartment lid (locked)
8 - Potentiometer, convertible-top compartment lid interrogation
9 - Microswitch, left/right rear section flap up and down
10 - Coding, control unit for rear comfort system
11 - Microswitch for lower part of lid lock

This diagram may give you an idea where to start. There is also a possibility you may have fault values stored in the upper left/right flap micro-switches (#7) and this could be read by PIWIS II system. These switches are activated when the top is opened and set down. Also main control unit (#6) could be bad or the potentiometer (#8) is reading faulty voltages. I would expect either of these to have error codes in the convertible top module in the DME unless #6 is bad.

Finally there are three electrical checks for the top to activate properly as long as:
• Terminal 15 is connected via ignition.
• No speedometer signals greater than 50 km/h (30 mph) are present.
• Engine compartment lid is closed (input not at ground potential).

The first two items are non-issues as long as the top operates when ignition is on and vehicle is less than 30 mph. The last item may be a possible issue if the sensor that reads the engine compartment lid is bad, thinking the compartment lid is open. Personally I think this is a remote possibility to your "Not in Limit Position" message.

If nothing seems to help, you could always ask the shop to recalibrate the convertible top control module. In doing this the shop would / should be able to see if the switches and potentiometers are working properly. Sort of like a reboot; and if there was some internal error, even one not read by the DME / control module, it would act to reset the system. Again, probably as a last resort option in my view. Sorry not much explicit help on this one. Electrical problems are mostly trial and error. Good luck.

powderzone

^^^^
Now there's a response!
I'm going to keep this handy just in case my cab top starts acting weird.

Crossfire190

Iceter... any luck sorting this out. I continue to have the same problem.

Wayne Smith

stronbl ... I've got a coupe, but I have to say ... Very nice write up!

Iceter

Stronbl, thank you for your fantastic write-up. Here's an update on my issue.

The weather turned warm and when I put my top down, the dreaded beeping and flashing reared its ugly head again--only this time, it was incessant. The car would warn me that the top was not in its limit position at least fifty times in the ten miles between my office and home. It was awful.

The silver lining is that there was no chance that the tech wouldn't be able to get the car to malfunction, which had happened before. With so many possible causes of the alert, they need the car to alert while it's connected to the diagnostic computer so they can isolate which of the many switches and potentiometers is sending the signal.

So, I took it in to Porsche of Southpointe and they were able to diagnose the issue right away. It was a malfunctioning microswitch (I believe the one for the convertible top lid). They had to order it but it came overnight. Replacement was less than $300 with my PCA discount and I can now put my top down and enjoy the sound of my car without constant beeping.

As an additional perk, I took the malfunctioning switch home and let my 7 year old son smash it with a mini-sledge in the driveway. It was a good day.