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Hoecht

996 Carrera Convertible top Calibration

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Just completed repairing and refitting the clamshell drive unit on a 1999 Carrera cab, set the potentiometer for 6.2K ohms, cleared all faults with durametric, roof opens to halfway point, then sets operation timeout fault, flashes warning indicator and ceases operation. My question to anyone who knows is "How do I calibrate the roof without the PST2" as Durametric does not offer this function. :help:

All window and roof functions are otherwise synchronized, I'm assuming the position of the roof was incorrect when I reinstalled the potentiometer.

Note, my brain is starting to hurt a bit, and I am re-kindling an old love of early cars. :thankyou:

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I have done it with a PST2 and it literally takes about 2 minutes (providing nothing is still broken).

I would try to fins a show with a PST2 and pay them for the minimum time to do the calibration.

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Just completed repairing and refitting the clamshell drive unit on a 1999 Carrera cab, set the potentiometer for 6.2K ohms, cleared all faults with durametric, roof opens to halfway point, then sets operation timeout fault, flashes warning indicator and ceases operation. My question to anyone who knows is "How do I calibrate the roof without the PST2" as Durametric does not offer this function. :help:

All window and roof functions are otherwise synchronized, I'm assuming the position of the roof was incorrect when I reinstalled the potentiometer.

Note, my brain is starting to hurt a bit, and I am re-kindling an old love of early cars. :thankyou:

I think durametric does have the calibrating in their program. Update to the latest version.

Just for your brain....

Kare

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Went to the dealer. Paid $155.00 so they could tell me the roof would not calibrate. They also suggested that it would be trial and error for the tech to find out what is the problem. I spent a few minutes discussing it with two techs, neither of which was much help. So I will see if I can get my hands on a wiring diagram, and get a look at the microswitches as the roof closes/opens to see if something is changing that shouldn't be. I wonder if the front latch has anything to do with it, as it moves to retract into the top just before the system faults-out and ceases operation.

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Just completed repairing and refitting the clamshell drive unit on a 1999 Carrera cab, set the potentiometer for 6.2K ohms, cleared all faults with durametric, roof opens to halfway point, then sets operation timeout fault, flashes warning indicator and ceases operation. My question to anyone who knows is "How do I calibrate the roof without the PST2" as Durametric does not offer this function. :help:

All window and roof functions are otherwise synchronized, I'm assuming the position of the roof was incorrect when I reinstalled the potentiometer.

Note, my brain is starting to hurt a bit, and I am re-kindling an old love of early cars. :thankyou:

What were the symptoms that led you to repairing the clamshell drive unit? I'm having problems with my top and I think it may be related to that unit. Any assistance you could provide with troubleshooting/repair would be appreciated.

Cheers,

Jim - 99 C2 Cab, Vesuvio, 6sp, Seattle, USA

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I wonder if the front latch has anything to do with it, as it moves to retract into the top just before the system faults-out and ceases operation.

Is the latch trying to latch before the top is in position? Does the Durametric show actual values for cabtop microswitches?

Edited by PTEC

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Repairing my convertible top this weekend. Things went well with the fluid install (was dry from previous owner).

I attempted the calibration via PIWIS, top goes through the entire process then stops before it tries to latch. Reversed and then complains of Timeout. Which microswitch would this be? Also where do I find the potentiometer to verify ohm at start?

Seems this should help me but still interested in folks feedback on possible issue: www.welton-village.org.uk/porschesofttopp.pdf

Edited by 987_RDC

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You need the workshop manuals. They detail pretty much any fault and the required service. Also the durametric does have a function for fault codes and a calibration function that works for me.

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I believe I need the $9 latch cover since the final switch is not being pressed. This is in line with the error code of Timeout, only after going through the entire process.

996.561.787.000.1C (remove old remnants, snip circles and glue into place on top of metal latch)

Edited by 987_RDC

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Repairing my convertible top this weekend. Things went well with the fluid install (was dry from previous owner).

I attempted the calibration via PIWIS, top goes through the entire process then stops before it tries to latch. Reversed and then complains of Timeout. Which microswitch would this be? Also where do I find the potentiometer to verify ohm at start?

Seems this should help me but still interested in folks feedback on possible issue: www.welton-village.org.uk/porschesofttopp.pdf

I believe the last microswitch in the closing sequence is the one on the top of the Lid Drive Motor. This is shown on the last page of the PDF. You should be able to visually verify that the switch is being depressed by the latch sliding mechanism when the top is up and the lid is closed. (must remove the rear carpet first).

The potentiometer is mounted to the back side of this motor. You can get a ohm value from it by pulling the cable from the cabrio control unit, and measuring the pot. with a meter.

When I had issues with the lid mechanism, I found that the cable that drives the lid up and down was binding, preventing the lid from fully latching, and preventing the microswitch activation. I had to replace the lid drive mechanism.

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Update: The latch cover did solve the final switch problem and allows back windows to rise. But roof halts half way (Both directions) using the instrument button.

I can execute a calibration using PIWIS and the top goes from fully tucked away, travels all the way to the up position and the latch extends. But it doesn't attempt to latch, it just reverses and goes back to fully closed and clamshell covered/latched. PIWIS reports a timeout. Can others confirm calibration sequence should be like this?

I've manually checked all the micro switches with "input values" display on the PIWIS. The latch microswitch is functional and does confirm clamshell fully closed. Also if I halt the calibration (beyond halfway) I can confirm the dash switch fully closes the roof (roof latch microswitch activates). Back windows roll up and everything buttons up.

From roof fully retracted: Dash button opens clamshell, both flaps drop but roof fails to rise. (confirmed flaps switches indicate they are both down)

From roof deployed: Button rolls down windows, raises the clamshell and roof beings to move back. Halts halfway.

Help?

My next steps are to remove and lubricate the side flaps and also inspect the convertible top potentiometer. Perhaps that is bad or got knocked loose. Anyone have info on flap removal? Found potentiometer diagram on http://www.cabriolethydraulics.com/_pdf/Carrera_DIY,Inspection_Removal,Shipping_02_21_12.pdf which shows how to remove the hydraulics.

Edited by 987_RDC

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I believe the last microswitch in the closing sequence is the one on the top of the Lid Drive Motor. This is shown on the last page of the PDF. You should be able to visually verify that the switch is being depressed by the latch sliding mechanism when the top is up and the lid is closed. (must remove the rear carpet first).

Thanks for the tip. I had originally verified the microswitch functionality with manually pressing and then moved on. Your post had me remove the carpet behind the rear seats so I could clearly see the final latch. It didn't move as expected.

Seems the metal "foot" from the final latch has broken off. This slider is inside the clamshell drive and engages with the black metal piece after the foot piece starts the sliding motion. Thus the back latch never completes.

Borrowed img from another member's rear drive dis assembly: (part circled in red)

post-75189-0-38752900-1341021104_thumb.j

My piece with the "foot" snapped off that begins the last latch travel, the black piece engages with the slide drive after foot catches.

post-75189-0-29830400-1341021129_thumb.j

Hoping I can get help from friendly fellow Cabriolet owner to get a replacement part....

I also took apart the roof latch and adjusted the microswitch which detects touching the roof to be more sensitive, then adjusted the rear tension cables such that they are not "flopping" the roof down onto the frame but barely allowing the microswitch to be triggered.

Anyway. Hoping this thread can be a one-stop-shop for future Cabriolet owners facing the various issues causing issues. (beyond basic fluid replacement)

Edited by 987_RDC
  • Upvote 1

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Got a part from another kind member for few dollars. Popped it back in, executed calibration. SUCCESS!

Top works perfect now, awesome.

Parts to fix:

New latch cover

Safety clips

Hardware for clamshell

Replaced latch slider

Refilled fluid

Replaced latch protection flap

I believe the rear latch protection flap broke then the previous owner got the canvas caught and busted that foot off. From there the top stopped working. Not sure how they also busted the latch cover...

Edited by 987_RDC

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I think I have the same issue, as the micro switch is not engaging. Did you replace the complete drive assembly (996 561 021) or a part inside the assembly?

Thanks!

Chris

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The casing wasn't damaged and just replaced the pieces inside.

Edited by 987_RDC

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Bought them from another Carrera Cab owner who had other parts of rear drive broken. Don't try to MIG weld the piece but not sure if TIG might work.

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Is it possible to do the recalibration without a scan tool? I had my top replaced recently and it has not worked properly since. Ive had to replace on of the side base plates that the top arms attach to. I have also replaced the clam shell hinge arms, and my last problem was the same as 987_RDC. My locking hook for the clamshell would not lock and had the same broken part. I scored a complete gear drive for a good price but I can not get the motor to turn the gear. It runs but doesnt engage. I guess it has some sort of postion sensor (the blue plastic gear housing) that keeps it from engaging and breaking unless its in the correct postion.

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Tighten the left hand turn bolt yet? It has to not be fully tight nor fully loose. I think manual says # of turns.

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The reason the motor turns but does not engage is because the gear on the bolt is being pushed back by an internal spring. I actually put a second spring on the other side of the gear to keep it pushed in and engaged. Seems to work fine now

  • Upvote 1

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Am I correct that the mechanical parts of the convertible that open and close the top still work even after the emergency operation (turning counterclockwise top open the rear deck lid), but that things just aren't in sync? In other words, they don't completely close or latch?  

 

I am specifically curious as to whether or not the lid for storing the top stops opening and closing without doing it manually.  I am assuming it will still open and close electronically, just not with the correct timing, but now that I tried to open the lid manually, does the computer shut it off?

 

My top was closed, lid latched. Went to open the top and the main latch to the windshield works fine...detaches from the front and but then the lid wouldn't open, so the sequence of opening the top just stopped. I wasn't able to open the lid with the emergency tool, rotating it clockwise it just stopped to the point I was going to break something if I didn't quit.  Trying to rotate it back (clockwise) bolt actually came lose (it is reverse threaded). 

 

Anyway, I detached the 5 pin cable to the motor that open and closes the lidr. There are 5 pins on it. I couldn't get colors on the wires to match what was shown in the wiring diagrams of the Porsche manual, so I used some logic in tracing the wires and it looked like the solid green and solid gray wires were supply voltage to raise and lower the lid.  The other three look to do with the potentiometer. I assumed ground to the motor was established from it being bolted to the chassis of the car. Applying 12 volts to either of them did nothing. But when I plugged it back in, the deck lid finally opened normal and the top was able to lower into the compartment without issue.  However, the top lid did not close, and since then does not work electronically at all.  I can now open and close it manually though.

 

So I was wandering if the computer has shut of the operation of it until it is calibrated again.

 

 

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I can only supply one data point for you.  I have mechanically opened and closed the top when I had issues years ago, and the electronic actuation did not stop.  I'm not exactly sure what calibration actually does?  But in my case it was not necessary to get the top working again.

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