Calibration 996 top with PIWIS

Hey all, i have a 99 996 Cab which has a top which won�t fully cycle after some repairs. Replaced the clam hinges which had snapped, checked the fluid level, clam drive shaft, checked the flaps and sensors. Someone has offered to let me use their PIWIS to calibrate but I am not sure of the steps, position of items, when to calibrate the clam pot resistance? Anyone have instructions or a diy for this? thanks Taffy

Every time you have to calibrate it the front locking mechanism has to manual put into the calibration position. People say it’s easy but to me its a huge PIA. Especially if there’s multiple repairs needed and one is hiding. The last one I did need the worm gears replaced. Wasn’t obvious and that’s what became annoying.

Thanks Flatlined, i have read the instructions to manually move the locking mech which is not that bad vs trying to get the damn thing to lock onto the screen using it! But there is not set position which the roof itself needs to be in? I can just partially open, pull the locking mech back and kick off the calibration process? Thanks, Taffy

There’s two white dots on one gear and one white dot on the other. That single dot has to lay in the middle of the two. Then install the mechanism back and have the top closed but not locked or actuated. If it stops at any point then there’s something else that needs to be fixed.

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Taffy can you share these instructions to manually move the locking mechanism? maybe a website link?

The place I used cant be viewed by anyone. It’s an invite only. However like I mentioned. Start the calibration with the top in the position right before the top locks to the front windscreen area. Then just click calibrate. It will lock the top then it will unlock it and open the top fully. If it stops at any point that is bc there is something still broke. There isn’t a per say start position but that is how I always performed it.

Not more more in POSES that this: Ran through simulation mode on my PIWIS there is an option for calibration - although what it does im not entirely sure:

Hey all, to follow this up we ended up trying to calibrate the top with the PIWIS II but the solenoids made a few clicking sounds then the PIWIS gave an error of "end point not reached" and the calibration stopped. We did follow the factory manual and took off the mechanism that locks down the roof and put it into the calibration position - still no luck. The roof gets about half way then just completly stops... Any ideas? Calling Porschetech3! Help please! I don't have much cab experience as mines a coupe but any assistance for Taffy the OP would be much appreciated! ​​​​​​

Let me see if I can help. Seems as there is a problem with the clam shell drive motor since the hinges were broken. Start by removing the clam shell drive motor and reset potentiometer to 6.2kohms as per WM 61-70-19( make sure both drive cables are working) Then recalibrate top system with PIWIS. Recalibrate can be started in any position but to set the clam potentiometer it has to be in "service position". The control unit will calculate the "end stops" of the drive motor position during the calibration process. Try that first. If you still have problems, the most common things are the potentiometer for the hydrolic rams located on the drivers side hinge(plastic arm breaks and potentiometer doesn't move, can be read with PIWIS), the end stop switches for side flaps (can be seen and flaps actuated by PIWIS), the microswitch at windshield frame (can be switched with your finger and seen in PIWIS).

Thanks Porschetech3! We did try and run the calibration from a few different positions with the same error. We reset the potentiometer to just over 1v as the piwis read volts not ohms? Also Taffy's roof locking mechanism was broken - guessing that might be an issue

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To reset the clam shell Potentiometer to 6.2kohms it is done with a DVOM on pin 3 and pin 5 before installation. In PIWIS the POT should show a little over 1v fully open and a little under 3.9v fully closed. So you may be close enough to calibrate. What makes you say the roof locking mechanism is broken? Did you do an Emergency Open? After doing an Emergency Open you have to do a 8 step repair procedure as per WM 61-01-41. It repairs/resyncs the roof latching mechanism.

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Thanks Porschetech3! We adjusted the potentiometer with the roof half closed (from memory) maybe we should have calibrated when it was fully closed instead? The locking mechanism was missing a part off the hook but I think Taffy would be able to explain better. We did follow a repair procedure of the latching mechanism but which one it was im not sure. I've contacted Taffy so hopefully he can share some more detail. Cheers and thanks again for your help as always!!

Hey Guys, We adjusted the calibration with the clam open using PIWIS but didnt have the volt meter on me to check ohms could only check the pot2 voltages, it was installed at 6.2Kohms with the clam open as well. So will need to redo that. The hook is the centre hook which latches the roof to the windscreen, the plastic cover has come off and i have heat shrink on it at the sec so that it engages the windscreen switch. If you dont do this you cannot move the rear side windows. The instructions which we had when we ran it through PIWIS was this: http://www.welton-village.org.uk/porschesofttopp.pdf Faults on the softop (Thanks to Dan for the PIWIS read out to get these. FYI Foxwell 510 cannot see the softop, will try the durametric in a day or so as have one handy at the sec.) 1 Switch position implausible 4 Potentiometer fault, convertible top compartment lid 5 Maximum time exceeded (timeout) 6 Calibration required 7 Supply voltage Not too worried about 7 as this was a common error as we ran this on the battery without the engine from memory. From this i am going to guess its the Pot on the clam which is not showing the correct voltages when open to allow the soft top to continue to close, does sound right? The Clam does drive drive, i replaced the pin which goes through the motor and Pot as well as the RHS hinge which was broken. The Clam will drive open and close if you open the roof ~1/4 and then close it again. The roof was operated manually during this, which was a stupid thing to do in hindsight as it did full cycle before i replaced anything once you manually moved the clam to open. To calibrate the pot on the clam drive: Open Clam into service position (61-20 install step 1), set to 6.2Kohms close clam? (Does not mention that on 61-20 install step 3), check voltages on tester 2 (P2-1: >1.0V, P2-2 <3.9V, P2-3 <3.9V, P2-4 <3.9V) Thanks, Taffy

Side flaps seem to be working: Parameter code 0.0 C alibration detection 88 Latch locked Catch locked Latch unlocked Catch not unlocked Convertible top Convertible top raised Convertible top compartment Convertible top compartment lid unlocked Right side flap up Right side flap not up Right side flap down Right side flap down Left side flap up Left side flap not up Left side flap down Left side flap down Speed Speed >5 km/h (3 mph) Roll-over protection Roll-over protection retracted Handbrake applied L atching hook Latch hook not actuated Engine-compartment lid Engine compartment lid closed Convertible top button Close convertible top button a ctuated Convertible top convenience function Convertible top comfort opening actuated Supply voltage 12.99 V Warning light on 5604.5 min Actuation counter 1 1001 Actuation counter 2 464 C alibration counter 6 Potentiometer 1, convertible top 1.08 V Potentiometer 2 (conv. top compartm. lid) 2.02 V Calibration: Potentiometer 1, calibration value 1 - Calibration value 0.82 V Calibration: Potentiometer 1, calibration value 2 - Calibration value 1.35 V Calibration: Potentiometer 1, calibration value 3 - Calibration value 2.02 V Calibration: Potentiometer 1, calibration value 4 - Calibration value 2.49 V Calibration: Potentiometer 1, calibration value 5 - Calibration value 3.24 V Calibration: Potentiometer 1, calibration value 6 - Calibration value 3.51 V Calibration: Potentiometer 2, calibration value 1 - Calibration value 1.59 V Calibration: Potentiometer 2, calibration value 2 - Calibration value 1.88 V Calibration: Potentiometer 2, calibration value 3 - Calibration value 2.06 V Calibration: Potentiometer 2, calibration value 4 - Calibration value 2.78 V

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What am i looking for to see this? Thanks, Taffy Edit: Found an image in the car, but in PIWIS what am i looking for? http://www.cabriolethydraulics.com/pdf/fig16and17.png

Had a play with a Durametric today, kept dropping out on the surface pro 3 windos 8.1 i was using. Possibly a USB 3,0 issue. Will try it on my old dell when i get back home. Its really odd in that you can get in, get the cable connected and then run 1 command before it drops out and 'cannot communicate'. Grabbed a cheap volt meter to adjust the POT while i am away, will try tonight when it cools down from being 40C outside...

Where is top stopping at? When it’s saying that the calibration times out. I had one top that didn’t really show itself through piwis. It took me dissecting the complete system to understand where each part was and when each part was to be initiated and where it is supposed to start and stop at. This particular one was from both left and right worm gear motors that are located near the rollover bars. There’s two micro switches on each. You can also move them manually with an hex to set in open or closed position.

I made this video a little while ago and essentially we are at the same stage: You Tube Calibration wise it does nothing, no movement at all.

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I may have confused you about the 6.2kohm setting on the clam pot at fully open. I'm referring to the clam shell being fully open (service position )and not the convertible top fully open (which would be clam fully closed). The clam pot should show above 1.0v when clam is fully open and under 3.9v when clam is fully closed. Actuate side flaps using PIWIS "drive links" and check for open signal and closed signal from end switches shown in PIWIS. Using PIWIS "drive links" you can open close clam shell, open and close side flaps, open and close convertible top, open and close top latch, ect, and watch pots, and end switches for proper function. I am familiar with the "plastic cover" breaking off the latch hook causing the micro-switch in the windshield frame not to show when latched. I use a thin piece of plastic and superglue to the microswitch pad as a "quick fix" to make the top work on occasion. That plastic cover may be available as separate part now..I'll check to see.

Thanks Porschetech3, will see about resetting the POT and getting access to the PIWIS again to run the tests. I did get a durametric but having some issues getting it to run, keeps dropping out after running for a short time and wont let me see the convertible module at all before it loses sync. Have emailed the support team to see if they can help. Thanks, Taffy

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Hello I know it's an old thread but I am stuck at the same place after replacing the driving mechanist. Did you find out where the top should be when setting up the 6.2kOhms.? Also how do you measure the voltage if not using PIWIS? thanks in advance

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Sorry to butt in but this was the only thread I could find discussing Pot 2 values. My situation on my '99 c4 cab is a little strange. Top fully cycles, but my clamshell only opens about 95% of the way when lowering the roof. When roof is fully stacked, clamshell closes about 95% again, so that it is not flush with body. I've looked at all the threads and read the service manuals, and have some theories: 1. When the rams were rebuilt, and before the recalibration, the workshop manual calls for "compartment lid drive screw" to be turned till clamshell reaches a "perceptible stop". I'm guessing my mechanic did not wound that screw out all the way, and started recalibration at 95% of clamshell travel, which the ecu then saved. Is that how it works? 2. The roof itself is working fine. Can I put top in service position using dash switch, go to the rear seats and turn the clamshell drive screw till it's fully open? Does that count as an emergency open and prompt a recalibration? Here's the pot 2 value readings from my scanner: