Convertible Top Warning Light

Just had my convertible top repaired at an independent shop (broken gears) and now the top goes up and down as it should, BUT I get this warning light if I drive faster than 33 MPH (50 kph). And the windows don’t roll up all the way. Easy fix? Maybe something I can adjust with a hammer and a wrench, or tweak with my OBD scanner/programmer?

I'd call the independant shop to come pick up the car and fix it either same day (and deliver it back) or provide you with a suitable loaner (987 Spyder comes to mind...) OR if they can't do that, hand them an invoice for your time and inconvienience. It could be a number of things, theres a micro switch in the header rail, another micro switch in (I think) the drivers side roof gearbox, are the gearboxes synchronized? If you have a Foxwell NT530 you could try going into the rear comfort module feature testing and use the "open roof" and "close roof" tests to see if that ends in the same result. That used to be the only way I could open my roof, though the switch would close it. Cheers, Julian

Agreed, that would normally be the correct solution. However, I’ve had nothing but trouble with this shop and won’t be taking it back, even if it means paying for someone else to fix their fix. My hope is that I can manage this myself, maybe with my shiny new Foxwell NT530.

Good for you!! In that case I would check the timing of the two gearboxes first. And, could you describe the issue in more specific detail? Starting from roof closed and latched, is the rear clamshell fully closed? Are (both or one?) the windows all the way up (to the point that they do the 1/2" drop when you open a door)? When the roof is opened all the way, does the clamshell appear to be closed all the way? Do the windows go all the way up? Do you see the warning on the dash ONLY after you've gone over 33MPH?

1. The rear clamshell is slightly misaligned whether the top is up or down. The left side is slightly higher. It's not very noticeable, except to a Boxster owner. ;-) 2. Neither window goes all the way up when the top is up. They both stop moving well short of the top, with about 3" of airspace between the glass and the roof. 3. I get two different warning lights on the dashboard. When the top reaches the fully closed position (ignition on, engine off, car stationary) it says, "Failure convertible top ctrl." That's followed by "Convertible top not in limit posit." (in white). If I dismiss both messages and drive above 33 MPH the 2nd message reappears (in red).

the rear clamshell being misaligned really indicates the two gearboxes are out of time. Here's a snapshot of page 18 in the "Convertible Top" section of the manual.

Excellent tip, thanks. Now I have a starting point. If I read this right, fixing the misalignment is purely a mechanical fix described in Fig. 12 thru Fig. 21 in that section of the service manual, with no software/ OBD programmer involved. Looks like the goal is to get both lever arms to 195mm from a certain point on the bodywork. Fun times...

Sounds like you've already started readng up on the process but just in case it hasn't been pointed out, the gearbox is SUPER low geared so adjusting the timing marks by turning the cable by hand (after disconnecting from the motor) is the work of a thousand years. Put the end of the cable into the chuck of a cordless drill and save yourself some frustation.

Okay, it's better. Not completely fixed, but better. I followed the instructions outlined above, paying special attention to part about lining up the hash marks on the two transmissions, and the bit about measuring 195mm after reassembling them. Aligning the metal hash marks on the two transmissions did not result in the desired 195mm spacing on both sides. One side was considerably lower than the other. So, I tweaked one side to get the 195mm spacing. I guess that was the right move? My clamshell is still out of kilter, but at least the windows go up and the warning lights come on only about 50% of the time now instead of all the time. That's progress, right? Turning the ignition off and back on seems to help. Also, the top occasionally stops moving partway through its open/close motion for no apparent reason. Still, the fact that my tweaking helped at all tells me that more tweaking might help even more. Or it might just be a waste of time and creative searing. Opening and closing the top under control of the Foxwell NT530 gives the same behavior (i.e., flaky). It doesn't seem to be any more or less reliable than using the normal up/down switch. would Oh, and you're right. Turning the little "speedometer cable" by hand is a complete waste of time. I selectively connected and disconnected the cables from the motor and used the in-car switch to spin them the required amount. That's also a nuisance. I'll use a drill next time.

If its still out physical alignment, you can also adjust the arm that connects the gearbox to the roof mechanism though that wouldn't have (in theory) any affect on the clamshell. Have you tried removing the arms that connect to the clamshell and comparing them? One of them might be deformed in some manner. I just remembered there is also a limit stop for the clamshell, that hasn't been moved and stopping it from closing properly has it?

A-ha! So that's what those little black things are. Guess I should've read a few pages further along. I notice mine are labeled +3 on one side and +4 on the other. I may try adjusting or replacing these to see what effect they have on my clamshell alignment. When all the control arms, gears, and levers are disconnected I could raise and lower the convertible top manually, and also raise/lower the clamshell manually. Fortunately, the clamshell naturally rests in its fully open position, held there by gravity. But mine seems to be bent or misaligned somehow. The left side doesn't want to rest in its fully open position; it stops about 3/4 of an inch from the end of its travel. I can't see any mechanical interference. Nothing is binding or jammed. It just doesn't want to slide to the end of its track without some gentle pressure. My hunch is that some part of the hinge mechanism, or maybe the clamshell bodywork itself, is bent. That would be a bummer.

Hmm, so even when disconnected from the gearboxes the clamshell doesn't lay flat, that really sounds like its twisted (entirely possible given the gearbox jam/breakage that started all this). I would try to gently persuade it back to straight, those cast arms that connect the shell to the sliders are much stronger than the torsional rigidity of the clamshell so I would be shocked if they were damaged at all. Once the clamshell is straightened out again and naturally sits flat with the bodywork I would reconnect it to the gearboxes (still leave out the arms for the roof), make sure the roof is unlatched at the header and open/close the roof with the switch to see if it recognizes full operation and that the clamshell closes fully/evenly. If that that seems OK I would then open the clamshell enough to fold back the roof, close the clamshell and take it for a drive above 33mph. If that works you can reconnect the roof and continue on the path of diagnosing.

Take a very careful look at the bolts that hold the clamshell to the operating mechanism. And the spring-things to the clamshell (these don't compress - they pull the top down and expand - exerting spring force to keep the top down snug..) The reason I say that - we had someone with a similar problem with his clamshell, and it turned out someone in the past had adjusted the spot where the hinged mechanism fastened to the top - making it twist as it closed. In that case once I suggested it to him, and showed him a photo of what I meant (I'll try to find it.. but with 3000+ posts..) he looked and found not only had it been touched (the paint was broken where the bolts were wrenched on), but whoever did it scribed a mark in the top around the edge of the mounting plate before moving it. He moved it back to the mark and all was well again. Let me see if I can find that post.. So far I've found one with a similar problem: Convertible top lid not closing all the way (987.1) -... Still looking.. Problem with convertible top 2006 Boxster - never heard back on the resolution to this.. I have to giveup.. it's here - somewhere.. but where?

All the nuts and bolts connecting the underside of the clamshell to its two arms appear to be factory fresh. There's no broken paint or sign of removal. Not even any scratches. I'm pretty sure it hasn't been molested. As far as I can tell, both arms slide all the way forward on their horizontal tracks, with no empty space to slide any farther. And there's no debris in the tracks that would prevent them from moving all the way.

Have you made any new progress on your issue? I'm having a somewhat similar problem and am pulling my hair out trying to figure it out. One of the plastic ball joints on mine broke a little while ago, and I replaced it with a new one (I went ahead an replaced the other side as well since I bought a pair). I thought that should fix my problem, which is did somewhat. The roof was operating, but it was very clunky and the motor wouldn't stop automatically at either end of the up or down positions. And of course I was having the "Top Not in Limit Position" light (even though outwardly it looked like it was seated fine), so the windows would not go up all the way as a result. Then I noticed it had broken one of the ball joints again! I noticed the left side clamshell slide suddenly once and heard what sounded like gear slipping/grinding noise. At this point I'm sure that one or both side transmission gears are stripped/broken. So for now I've just disconnected the top and clamshell connecting rods so that I can operate the top manually and use the car while I work on the repair, but I can't get that pesky light to go off and the windows to roll up fully (and of course get those annoying lights and beeps when I go over 33). Is there a way to just bypass the light for now? I saw on YouTube one guy had converted to manual operation, and he says to just disconnect the microswitch at the roof top latch. I haven't tried it yet, but this does not seem correct to me. I have a Foxwell NT530 as well. Is it able to clear the error code?

Update: I am able to close the windows now! After disconnecting the clamshell rods I realized I can turn the transmission by hand. So I closed the soft top and latched it, then with the key in the ignition I rotated the transmission by hand until the "Limit Position" light went off and viola - the windows are fully operational now! I guess next weekend I'll begin the arduous task of removing the transmission to replace the gears. I'm going to try the driver's side first since that is the side that slid.

Okay, update: "What's Wrong with This Picture?" I just took a closer look at the photos I took to help me fine-tune the transmission gear alignment, and now I think I've been doing it wrong. Before, I thought each transmission had two alignment marks on it, but now I see there's really only one. The other mark is just scratched in, possibly by the independent shop that "fixed" my top. (The Sharpie marks aren't mine, either.) Here I was happily aligning both sides to the scratched-in marks instead of the official marks. This required only very small changes, so it seemed safe and sane. But now I see that they're both off by about 30-40 degrees of rotation. Yikes! So... do I realign both gearsets to match the official marks? Is that too much? Will it push the top or the clamshell too far and wind up bending or breaking something? How dangerous would it be to adjust the transmissions by that much? (Left transmission has green dot; right one doesn't. Scratches and Sharpie marks aren't mine.)

Pelican Parts has this on their article for replacing the transmission gear: With the transmission removed from the car use a drill (inset picture) connected to the cable to turn the transmission to the closed mark (green arrow). This will make marking the planetary gears easier.

Interesting. I hadn’t seen that before. But the Porsche service manual says to turn it to the permanent cast-in mark. I wonder if both marks are useful, just for different stages of assembly? Now that it’s in the car, should I be turning it from one to the other?

Oh, wait. I’m an idiot. Both marks are okay to use. Assuming both transmissions turn together at the same rate (as they should), they’ll be aligned to different marks at different times: the unofficial “scratched” marks at one point and the official “cast iron” marks at another point.

A bit of progress: 1. My clamshell will now lie flat. I managed to fix whatever twist in the sheet metal was lifting the left corner slightly. With everything disconnected, it sits perfectly flat just with gravity. 1b. I connected the clamshell to its two control arms (but with the fabric roof still disconnected) and cycled it up and down with the switch. It looks nice and flat every time. Hooray! 2. I then connected the other two control arms to the fabric roof and cycled the whole contraption up and down a few times. Car still complains that the top is not in its limit position, and the windows won't roll up. 2b. Also, the clamshell no longer lies perfectly flat. It's raised by about an inch, but it's consistent across the entire clamshell, as if it hasn't moved quite far enough. 3. I notice that if I latch the manual overhead roof latch thingie when the top is 99% closed, the motor stops moving. I don't think Boxsters normally do that, do they? And if I then unlatch the latch, the motion restarts, then stops a second later when it thinks it's done. That seems... not right. Edit: False assumption. Questions: A. Would adjusting the two ragtop control arms have any effect on the clamshell? The two clamshell arms don't have any adjustments of their own, so I don't know how else I'd tweak its travel or position. Does adjusting the fabric top indirectly adjust the clamshell, too? B. How does the car know when everything is fully open or closed? There's obviously the one switch in the center of the windshield header, but where else? I sure don't see any limit switches underneath the clamshell. How does it know whether that's fully closed or not?

1. and 1b - Yay! 2. and 2b - Seems like some part/sensor is telling the car the roof is closed enough but then another part is eventually telling the ...no, we're not done yet 3. Not sure I understand correctly here but are you trying to latch the roof when it's still "in process"? A. My understanding is no, unless per 2. something is telling the car the roof is "closed enough" B. I could have sworn there is a microswitch in the gearbox on one side....can't find any indication of such in the manual though....

3. Yes. Sorry I wasn't clear. Normally, I'd sit in the car and hold the switch to make the fabric roof close overhead. I keep holding it until all the automated motion is done and the motor mechanism goes quiet. Then and only then would I latch the mechanical latch on the windshield header. That's the way I've done it for years. BUT, now I notice that if I latch the latch a tiny bit early -- the fabric roof has touched the windshield header but the motors are still making noise -- it stops the motor motion. I don't remember the car doing that before, but maybe I'm just hallucinating. Edit: Answered.

I know that when you close the roof latch it presses a microswitch there which shuts off power to the electric motor, so it makes sense that it stops when you do so. IDK if this is entirely correct, but it seems adjusting the soft top arms shorter would allow the transmissions to turn further to the limit position, thus allowing to clamshell to go lower also? But it's odd that they've become so out of alignment with the clamshell position. I'm assuming you've verified that none of the control arms or clamshell arms are bent. There is a microswitch in the left side transmission (driver's side for LHD) that determines when it is in the fully open or closed limit position.

Yes, there is a microswitch (maybe two?) in the left side transmission. The blue disc in this pic is the cam gear that activates the microswitch(es).

If I had to guess - the factory marks are what should be used. I'm guessing here that the sharpie mark was made when the top was in service position - partly open - to help the person repairing it line the top back up after repairing the gearbox. When the factory marks are used, you probably want to remove the lid so you have access to that area with the top all the way up, and even perhaps disconnect the rear-bow cables (that hold the rear bow down) so you can pivot it up to get into the area. That's what I'd try. And yes - both gearboxes at the same set of marks. BTW - where do we get our cake?

Yup, you’re absolutely right. I just tested it by sticking my finger in the windshield microswitch and it stops the motor immediately no matter where it is in its travel. Dunno what I was thinking.

Since it appears that the arms for the fabric roof are the only things that are adjustable, I guess I’ll experiment with adjusting those. The arms for the clamshell aren’t adjustable, nor is the angle between the two. The left-side transmission spins by a fixed amount before stopping (and the right-side one just follows it), so that’s not adjustable, and there’s no software tweak to change the amount of travel. By a process of elimination, we’ve arrived at the solution! Or at least, a place to look for it.