996 TT Cabriolet Stuck Closed

[rrkf15c]

(Did a forum search and couldn't find anything this specific.)

My top is stuck in the closed (up) position. My local Porsche mechanic told me to take off the locking mechanism on the roof and check the micro switch on the windshield frame. That switch seems to work, however I think I have a bad micro switch on the locking mechanism itself. There are 3 micro switches next to the locking arm (Bosch) motor cylinder. I verfied one of them works because when I depressed it the top would rotate back and forth. But I think there is a micro switch that allows the locking arm to operate and that seems bad because the locking arm isn't moving at all.

I think my next step is to swap the micro switches to see if that's the problem. However, I've got zero experience with this so I'd like some advice before I proceed.

Here's a summary of the problem:

1. Red "top" light illuminated on dash...flashes 3x after 4-8 seconds

2. Locking arm inoperative

3. Rear lid opens & closes, but top doesn't move

4. Depressing one of the micro switches on locking mechanism allows top to move back and forward

Thanks for your help!

[rrkf15c]

Oh, here's a picture of the car for happiness sake...

[Duram]

Is the convertible top warning light on?

If you use the top a lot you may have hit the actuation limit. The 996 convertible top requires calibration and reseting of the activation counter after it has been opened and close a certain number of times. If you use a scan tool that can communicate with the convertible top module it may give you a fault code leading to what the problem is. If it is the actuation counter the fault code of "Calibration Required" may be returned.

[rrkf15c]

Thanks for the reply.

Yes the top warning light is on, and yes I use it a lot. The mechanic ran the calibration tool today and returned an error, but it didn't list a specific fault. He thought that might reset the system, but it didn't. I'm on his schedule next week to take a closer look.

[Duram]

With the factory tool or Durametric there is a function to "Reset actuation counter" that will reset it if that is what the cause is.

[rrkf15c]

Is the "reset actuation" a slow failure or all of a sudden?

[Loren]

I think the reset just clears the fault and makes it try again.

[Duram]

There are two types of reset, "Reset Light" and "Reset actuation counter" the Reset Light clear the fault and tries again. The Reset actuation counter does just that. You can also see the counter value in actual values, and verify the reset after the command.

[rrkf15c]

Thanks, I'll inquire about the counter next week. The top did slowly start to have problems, i.e. the light stayed on after the top was closed. I would open it back up and close it again, and it cleared the light. Then after about 2 weeks, it took 2-3 open/close to clear the light. Now finally the lock arm doesn't move at all, but the back lid does.

[rrkf15c]

I followed the owners manual to close the top so I can take it to the shop. When I tried to manually open the locking arm in accordance with the proceedure, the gear wheel wouldn't move. I took apart the locking mechanism and found that the motor is binding. I removed the motor and the arm rotates fine. Therefore I wonder if I need to order a new motor (pictured)?

I was able to open and secure the top...makes a 40 degree drive a bit cold, but fun nonetheless. (I love my car.)

[rrkf15c]

After taking this to the shop and explaining that the locking arm mechanism was binding, the mechanic proceded to take the better part of a day to figure out that I needed a new locking mechanism. The car isn't fixed, yet they left a message that the total charge is $400+ for shop time (I guess). I haven't had a chance to talk to them, but does this seem ridiculous? I know these cars aren't cheap to fix, but I went in there and told the guy exactly what I thought was wrong. Can someone be the voice of reason here?

[wross996TT]

Was the shop you took it to a dealer? If so that is the usual Porsche tax. This is why you need a good indy. I have never heard of an actuator counter nor the need to reset it. I do have the entire repair manual and training manual and have found nothing about this? If you would like I can email you the training manual for the soft top (7mb file).

Edited January 5, 2013 by wross996TT

[rrkf15c]

I took it to an independant. The receptionist left me a message Friday night, and I haven't been able to talk to anyone. Therefore I don't know the whole story, but I will post it on Monday. Bottom line, sounds like it needs a new latch mechanism. There are plenty of them for sale on ebay, so hopefully it should be an easy fix from here on out.

Thanks Wross, I'll pm my email to you.

[rrkf15c]

Getting a 3 minute cryptic email from the repair shop receptionist is to be taken with a grain of salt. She got the details AND the total charge wrong. The mechanic ran through a laundry list of items to come to the conclusion that a new latch is needed. He thinks it's a failed microswitch in the mechanism itself that was continuously returning a fault code. My regret is that I didn't try to tinker with it a bit more to see if I could've figured it out. Regardless, the top needs to be recalibrated anyway once the new latch is installed.

Now I need to decide if I want to buy the upgraded part for $1000, or go to ebay for $250. I figure I'll take a chance on Ebay since I can buy 3 used latches for less than a brand new one.

[987_RDC]

Buy used one and list your for sale as parts. Could help out someone else.