As I mentioned before, my latch hook extends and retracts too early. I hoped that by running a top calibration it would relearn the final open and closed settings and the hook would operate at the correct position. Unfortunately, it didn't. And I've also determined that all my microswitches are working correctly and the hydraulic rams have no leaks. So, the next reasonable suspect is the potentiometer. I'll tackle that over winter. BTW, there are two potentiometers - one for the top (non-adjustable) and one for the clamshell (adjustable).

On the Foxwell, navigate to the Convertible Top Control System menu and run a calibration. It's that simple. Make sure you have a healthy and fully charged battery. You might even be able to do it while the car is running to be sure, though I've never tried it that way. It's pretty important not to run your battery down.

 

OK.

On the adjustable clamshell potentiometer, it appears its under the rear quarter panel trim (passenger side), manual page 184 (.PDF)

 

There are mutiple sensors and potentiometers that control the opening/closing convertible tops. I experienced the same problem(clam shell failed to close completely when lowering the convert. top), Replaced potentiometer and problem fixed. Later the clam shell failed to even start its closure routine from the fully extended position. Replaced a different potentiometer and problem fixed.

 

For the 1st replacement, was it behind the right rear quarter panel moulding ? How did you calibrate it after replacement ?

 

I don't have any details; work was done by an independent Porsche facility.

 

For the past 2 years I have been on a mission to eliminate the "convertible top not in limit position" errors on my .1. For my car, this only happened when the top was up and sometimes it would only throw the error once or twice and other times it would be constantly popping up the error. From an electrical standpoint, the .1 top has 9 microswitches if I remember correctly:
1 for the windshield where the hook latches
1 for the clamshell
2 for each side flap
3 for the latch if I remember correctly.
You can test all of these with a multimeter to validate they work correctly. To test the slide flaps and latch will take some disassembly. You can also use a screwdriver to test the windshield microswitch to see if that makes a difference when the top is in an error state.

There are 2 potentiometers:
1 for the clamshell that is attached to the clamshell motor
1 under the driver side rear panel that determines the top position

You can use a Foxwell or Durametric to read the actual values of these potentiometers. What I found with my car is that the top position potentiometer had a periodic voltage spike when the top was fully up or fully down. This spike was about 0.7 volts above the baseline. I replaced the part for about $225 and it was easy to do although you will need to de-pin and re-pin the wiring harness connector to install the new part and then re-wrap about a foot of wiring harness. Afterwards you will need to calibrate the top. I no longer have the voltage spikes and while I'm not ready to say that it is completely fixed, I have not had an out of limit position error since replacing the potentiometer.

 

Terrific post! Thanks for listing all the points to test/fix.