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Intermittent cab top operation

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Just looking for any ideas...

I have an '04 996TT cab. I have had 3 instances where the roof failed to operate. I have the SmartTop Module installed. The first 2 instances I would hear a clicking sound in the back and the dash light would flash, but no movement. After letting the car sit for several hours and driving it the roof would all of a sudden start working again. The third instance...last weekend, the roof went part way up then stopped. I have checked fuses (4 of them), tried using the key to open, the dash switch. I removed the SmartTop module as well. Any ideas? TIA.

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I am fast loosing confidence in this smarttop unit. I have been considering buying one but I keep hearing about problems with it installed.

Also is way too expensive here in the UK £175 = about $400!!

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It may not be the SmartTop, but what you are describing sounds to me like the low hydraulic fluid condition. I had this problem until, took it tot he dealer, they fiddled with it and "filled" the hydraulic. It worked for a few weeks, a bit better but not perfect. Then I refilled the unit myself, easy to do, and it has been working perfectly ever since.


The link will take you to the DIY. Cost is almost nothing, since I used John Deere hydraulic fluid (about $4) and a small child medicine syringe (free at the drugstore).

You can always remove the SmartTop and see if that cures it. But if you have to remove it, might as well check and add the fluid, same amount of work to get to it.


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I am fast loosing confidence in this smarttop unit. I have been considering buying one but I keep hearing about problems with it installed.


Note that he said he had removed his SmartTop, and the problem remained. I would think that eliminates the unit as a source of his problem.

The other recent thread on the Porsche forums regarding a RemoteTop problem included the poster's admission that he had "bent some pins" & "crossed some wires" attempting the installation. Certainly can't be blamed on Wilhelmy.

I have posted, and noticed a few other simlar posts, that my SmartTop unit at one point did not function as intended. In every instance I have read, here and on RennList, the poster reported that the company, once contacted, provided technical support and quick replacement, no questions asked. There may be complaints regarding their customer service, but I have not seen any.

The bottom line seems to be that, (annecdotally, at least) among Porsche and the commonly used third-party suppliers, the SmartTop folks do at least as well as anyone else out there when it comes to quality of product, technical support and customer service. It may be too expensive for you .... or you may simply choose not to purchase one .... but I don't believe anything I have seen posted here is reason to blame the SmartTop for cab top problems, or to "loose confidence" in the product or the company.

No relationship with Wilhelmy, other than as very satisfied retail customer.

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Sounds right. After reading the post again "post-morning-coffee", he took out the SmartTop and it didn't make a difference.

Statman, if it is under warranty (being an 2004), take it in. My best guess still is the fluid, and they should fix it under their nickel, check for any sensors, etc.

If not, you could fill it yourself, piece of cake.

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Thank you for your replies. Yes, I did remove the SmartTop and have sent it back to Stefan (Wilhelmy). We don't yet know if it is the module, the top mechanism or an interaction of the two. I am not suggesting it is the module only that it has not been ruled out...and I hope it did not cause any electrical damage. (I love what the SmartTop does BTW). I have an appointment with the dealer and I just want to be somewhat informed as to what they might do. Fluid, motor, electronics, sensors, switch, (any others?), etc. I like to be informed about options before going to the dealer. I'll let you know what I find out. Thanks again!

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Sounds like a problem with the hood control unit.

I had a similar problem, took my car in for a service and the Porsche dealer decided to re-code the car as when you opened the door the mileage etc didn't come on, not that I asked them to.

After that the hood would only raise and lower on the remote. They said the hood control unit was faulty but denied they messed it up when they re-coded the car, they blamed the smart top I had fitted which frankly I don't believe.

I would start with replacing the hood control unit, its the one behind the rear seats that the smart top plugs into.

After they replaced the unit the hood would only raise and lower on the button with the handbrake on, not something it used to do, however they have re-coded the car today and now everything is fine.

Haven't re-fitted my smart top yet but can't see why this should be a problem after all even when the hood was only working on the remote all the smart top features where fine.

Incidentally, Porsche used to do 2 different hood control units, one for 02 and before cars and one for 03 onwards cars.

They now only do one version and when fitted the car has to be coded to tell it what year car it is on so it has the right functions for the car of that year.

Hope you might find this helpful.

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