996 Cabriolet roof problems

Hi USA from a new member based in the UK. I am a Porsche enthusiast recently retired with a life long facination for the marque. My main interest is in the old timers and currently have a 356Sc , a 1971 pre impact bumper 911, a 1985 wide bodied 3,2 Carrera and a 994 track car. All easy to repair and understand and a good pension. I also own a 996 C4S with low miles and total reliability. To keep my hand in and with plenty of time on my hands I have also bought a year 2000 996C4 cabriolet in need of restoration. With all its electronic controls it is not easy to understand when things go wrong. Part of this restoration included replacing the complete roof and frame which is causing me problems. If i operate the roof to the closed position everything works in sequence through its cycle. If i open the roof it operates until the roof is in the fully open position but the clamshell panel at the back will not close. I have spoken to Porsche who suggest it needs re calibration on their computer however i believe that it is not getting a signal that the roof is fully open to then close the clamshell via the cable and motor system. The clamshell works perfectly when putting the roof up so that part of the system does work OK. Does anyone know if there is a limit switch or proximity switch that should operate to indicate the roof is fully open and to signal the clamshell panel to close>? Thank you in advance for any help.

https://rennlist.com/forums/996-foru...tuck-open.html

Trying to remember how the system knows the roof is in the fully open position. I know there are limit switches on each of the "wing flaps", so check those. Also make sure your engine compartment lid is fully closed. I believe the system knows the position of the top via a potentiometer that rotates as the top moves. This is what requires "calibration". I think there is a separate potentiometer for the clamshell compartment lid position.

More info on the Cabriolet top operation... Check the potentiometer readings on #5, which looks like it's located at one of the hydraulic cylinders.

Thanks guys. Just where do you get this information from??????? If you ask in the UK the usual reply is "take it to the main dealer for investigation" This info has given me a lot of things to check which i shall work on in the next few days and report back. Thanks again Peasoup39

You might find this link useful peasoup39. Some of the collected 996 knowledge is there.

The first part of the up or down sequence is the side windows going to the down position. If they don't start to go down, then nothing will work. The dash top will flash on the dash board and you will hear a double click from somewhere around the rear shelf area. If the side windows goes down, that is the indication that all is clear for the sequence to start. Then the rest of the up or down sequence should start and complete the entire operation. Have you tried the operation via the key in the drivers door position and not from the dash? Hold the key to the left and the top comes down (clam should close and windows should come up to the closed position). It appears that maybe the canvas is not folding correctly. Use the key in the door method holding the key to the left and help the canvas with your right free arm to fold one time into and under the back window. My canvas needed to be retrained to fold correctly and I have had no trouble all this summer. The first summer in 4 years since retraining the canvas. Hopefully the clam should kick into closing mode and come down and click into the rear centre latch. The side windows will not come up until that latch is closed or making contact. So there must be a micro switch in the latch which makes contact and then the final part of the cycle comes into play (which closes the side windows). Hope that helps somewhat.

Hope you don't mind my question on your thread. I'm having some serious roof problems. When replacing the hydraulic cylinders, I failed to properly balance them, which resulted in damage to the driver-side roof frames. I'm in the process of replacing it now, assuming I can find the parts. Would appreciate any good leads on a trusted wrecking yard that might have replacement parts at a reasonable price. Also, does anyone know where I can find a more detailed description of how these parts work together? The service manual I have doesn't provide the level of detail I need. 2001 996

Hi ronoran65. Sorry i cannot help you. I am based in the United Kingdom so giving you UK breakers will not be much use to you. When i changed the roof frame i did not disturb the cylinders. i just undid the fixing bolts slipped off the cylinders and replaced them in the same position. Replacing a complete roof frame with the cast alluminium brackets is straight forward. It simply requires the bolts to be removed. Cylinders slipped off the end pivots and the electric plug disconnected. Just make sure you locate the operating arm for the potentiometer over the sliding pin before tightening up all the bolts. Under the front of the cast brackets are two small height adjusting brackets. Mrak these and slacken them off otherwise you will snap off the tops and loose the adjustment.

Yes you are! I'm new here and still learning how it all works. Thanks!