C2 cabrio roof issues

[YPVS]

I love this info. I directly applied voltage to the drive motor. The spline gear is moving fine but the square centre pot isn't moving at all. When I checked the resistance after, it was still at 6.35k ohms. But if I manually move the lid, the lid moves fine without any binding and the connection where the motor goes spins. So I think the drive mechanism is fine. Although the top cable where the microswitch doesn't move at all. Maybe that only moves when the motor is driving it? Do you remember the repair kit part number you bought? Maybe I need that?

There are 2 repair kits, pre 2003 and post.

Pre

https://www.ebay.co.uk/itm/183896934521?hash=item2ad11c8879:g:E5gAAOSwrtFbUJ~i


Post

https://www.ebay.co.uk/itm/192602959382?epid=1516398578&hash=item2cd807ee16:g:E5gAAOSwrtFbUJ~i

I also had a quick look at the clamshell latch cable driven microswitch and you are correct. Mine shows open circuit when the switch is operated and closed circuit when the switch is not pressed.

 

[deMort]

logically you would instal the CTL potentiometer with the CTL fully open ( calibration 4 ) and at 6.2 K .. use the below image plus the previous one i posted on the positions .

I have however been unable to find anything proving this .. it depends on whether the Pot resistance goes up or down .. if down then yes ( voltage increases ) .. if up then no and it's the opposite and is fitted with the CTL closed .

It sounds to me like the potentiometer might not be working .. the control unit needs to see an altering value .. you can test this with an ohmmeter on the pot .

 

[martin t]

If you have a problem with the latch cable, I have a brand new one i bought from Porsche but did not need (thank you so much supposed Porsche Indy technician...not).

 

[martin t]

How did this happen?, ah must have pressed the quote button]

 

[YPVS]

logically you would instal the CTL potentiometer with the CTL fully open ( calibration 4 ) and at 6.2 K .. use the below image plus the previous one i posted on the positions .

I have however been unable to find anything proving this .. it depends on whether the Pot resistance goes up or down .. if down then yes ( voltage increases ) .. if up then no and it's the opposite and is fitted with the CTL closed .

It sounds to me like the potentiometer might not be working .. the control unit needs to see an altering value .. you can test this with an ohmmeter on the pot .

Aha, you must be psychic!

Yes, my plan for tomorrow, when my 9v batteries have charged over night, was to turn the motor anti clockwise a few revolutions and see if the POT resistance increased or lowered, as anti clock is raise CTL and clockwise, lower CTL.

I figured, higher resistance would equal lower voltage, so your helpful doc should confirm whether the POT should be calibrated with the CTL fully up or fully down and locked.

Cheers for the document. That saved me a job!

 

[dcapper]

I am so impressed with all the help. Well dummy here skipped a step putting the pot back in. I tightened it snug. When I was supposed to put it in with 3 turns. I pulled out the unit and did the 3 turns then put power to it. I put voltage to the motor and it spun as well as the centre pin popped into place. I am going to put it all back in later on tonight. I'll post my findings.

 

[YPVS]

I'm leaning towards the control unit now.

I've calibrated the CTCl POT again and reconnected with the top lid up. Still won't calibrate and all input values look correct, other than the roof position.

I've checked the POT on the left ram and the arm is connected and nothing is snapped.

The POT values are in the correct range for the position on PIWIS. With roof up and clamshell down, PIWIS shows 0.98V for the convertible top POT and 1.24V for the CTCL POT.

The stored calibration point 1 values (roof up clamshell locked) are 0.86V for POT1 (roof) and 1.57v for POT2 (clamshell). So the current readings close to the previously calibrated and stored values. Obviously I can't recalibrate as, like all other actions in PIWIS, within 3 seconds of pressing F8 it stops the action with "Function inactive - end point not reached".

The only thing of concern which I still have to address is the RHS flap seems to be stuck down and didn't rise with the other when the roof was lowered, which it sometimes will do after stopping half way, either from the key of button.

I'm a bit annoyed with this, as I also bought a second hand LHS one from the same Ebay seller and after fitting that one I noticed it was missing the plastic sliders which connect it to the ally rails, so have had to remove and rebuild from my own spares and refit. It now looks like both were faulty. If this one's motor is shot, at least I have spare assemblies with other faults to nick parts from, so for £50 each, for the entire assembly, there are plenty of parts there.

The replacement control unit is on it's way from the US, so hopefully that will resolve my issue. I can repair the other flap in the mean time.

On the plus side, my knowledge of the 996 sort top system has improved dramatically over the last few weeks, with plenty of help from DeMort and his pretty handy Service Manual pages, which I now have printed and kept in the car to reference. :thumb:

 

[deMort]

If you have a problem with the latch cable, I have a brand new one i bought from Porsche but did not need (thank you so much supposed Porsche Indy technician...not).

Thank you for helping me re-evaluate why i bother coming here .

 

[YPVS]

The quest continues...

I've repaired the duff flap and it works as it should.

Everything seems to operate as it should except anything in PIWIS stops almost immediately after starting with "Function Inactive - End Point Not Reached" and the top shows it's not raised even when it is at fully up at it's POT shows a voltage in Value 1 (fully raised and locked) range. Halfway, the roof seems to show the correct description in PIWIS of roof raised, but when allowed to fall completely, it still seems to think it's raised.

The thing is, both Potentiometer voltages are falling pretty much where they should be for all 6 stages of the roof and all 4 of the compartment lid. I've moved them about and checked voltages in PIWIS, so both POT's are working.

Once up, I can use the button on the dash to lower the roof, everything does it's job, the clamshell raises, latch unlocks, roof retracts, but this stops half way, with both POTS at 2.51V.

From there it sits with relays all around the car clicking when you try to up or down the top from there.

If I manually raise it a bit by letting pressure out of the bleed valve on the top pump, and pulling the top up. I can then tighten the valve and using the button on the dash, it will close, latch the roof and lower and lock the clamshell.

Very odd. I'm getting to the end of my idea train now, so may have to wait for the control unit to arrive from the US. It's cleared export customs and will be on a flight soon.

 

[dcapper]

How did you make out? I took a step back. But I went at it tonight. I did the pot steps all over. I got it to 6.2k ohms. Then put the pot back on the motor. But the next step after re-installing the motor is to manually close the lid. Well I can't, it's on fully extend. I'm just letting the blue loctite dry and see if it will calibrate itself. Unless you think I missed another step. I know my problem is in motor on the lid.

 

[dcapper]

New update. I'm getting somewhere but not too far. I got the lid to close and open with the button on the dash. The switch in the windshield had a broken wire. So here is the new dilemma. When the top is up the piwis shows it's closed. When it's down the piwis shows it up. The roof won't operate on it's own. I have to manually close it or open it. I do hear motor noise but nothing is happening. Do I have to release pressure on the pump?

 

[YPVS]

You've checked the obvious, like fluid level in the hydraulic pump unit, I take it?

If your tops says it's still up when it' down, what are the POT1 readings in the "actual values" in PIWIS? It will show the current voltage of the 2 POT's, then list the currently stored calibration voltage values 1-6 for the roof and 1-4 for POT2 (clamshell). This tells you where the POT is telling the car it's currently at. Mine is odd though. The POT is showing within the range for closed/up when it lists the roof as down.

Going by DeMort's document on the last page, 1 is fully closed/up for the roof, 6 is fully open/down. The clamshell is 4 for fully up and 1 for fully down.

 

[dcapper]

I topped the fluid up after the emergency closure. So that fork/finger switch seems to be reading in the PIWIS backwards. When the roof is closed, the PIWIS shows it opened. If I push up on it with the roof half open, the roof says open which is wrong. If I let the switch down then PIWIS shows the roof closed. Something is backwards. So when the roof is trying to open or close it would do the opposite yet it's not moving.

 

[YPVS]

Are you talking about the fork on the roof latch?

I'm on about the POT which is on the left hand ram and driven by an arm connected to a pin on the ram. It's position is supposed to tell the control unit what position in a range of 1-6, the roof is in.

PIWIS will show it's current voltage and the last 6 saved voltages for each position. Mine is showing around the expected voltages for the various roof positions, but PIWIS incorrectly says it's up or down, when the POT readings look correct.

I wonder if I need to look at my latch mechanism? I never did an emergency open of Roof latch itself, only the clamshell door. Because of this, I've never set the dots on the cogs. Maybe the roof latch also reports position?

Unless I'm Reading your post incorrectly, we may both need to look at the latch.

 

[dcapper]

I adjusted mine in the gear and I definitely got farther along. Make sure you check the switch on the windshield part too. Now I need to see what you mean about the clamshell switch in the back.