Z4 Top Problem - $20,985 Solution

P

PennBruce

Member
I found this forum while researching Hall sensors on E89. I am thinking my problem may be a misaligned sensor.

I recently installed a rear view camera system. I did this just after I put the Z back on the road so I hadn't driven it for five months. Finally had a warm day and I tried to put the top down.

Here's a video showing the problem:

https://youtu.be/O9JesM1avPQ

The dealer couldn't fix it, so they brought in a factory rep. He decided that I must have bent the top mechanism when running the wires through the trunk. His theory is that I left tools in the upper area of the trunk and then put the top down. His evidence for this is a minuscule paint chip on the leading edge of the rear window.

youtube].jpg

I ran the wires down the passenger side of the trunk. There is a sensor in the area so it is possible that I knocked it out of alignment.

The dealer thinks it's a software problem from the rear cam installation. So the next step is to remove the cam and have the software reloaded, $247 my expense.

Their ultimate solution is to replace the entire top at a cost of $20,985 my expense.

Has anyone else had a similar problem with the top? If so, I need to hear from you.

Thanks,

Bruce
 
Hi mate, how about a bit more info about you and your car. You will get a better response from the forum members if you give vehicle details etc. Oh and some photos don't hurt either :poke:
Sounds like the dealers are taking your pants down by the way.
Welcome to the forum :)
 
http://www.z4-forum.com/forum/viewtopic.php?f=46&t=95385

Look at the roof main hinge section of the post above , it looks to me like your roof is not latching into the boot storage position correctly , the micro switch isn't being triggered to then close the boot as the roof isn't locked correctly in the boot .

The hall sensors are fitted into the Rams on these so unless you removed the sensor it's unlikely you knocked one out of position , they take a lot to move them from there fitted position . The only one in the passenger floor pan (RHD car) is under a plastic trim cover that the boot partition locks onto for roof opening and if that was out of alignment the boot partition wouldn't trigger the roof to allow any opening at all, so it's not that sensor either .
 
Dietcokeman,

There are two prongs on the top that appear to lock the top down in the closed position. It seems that it should use the same method to lock it when it is open. However, there doesn't seem to any mechanism that locks the prongs when the top is in the open position.

Bruce
 
PennBruce said:
Dietcokeman,

There are two prongs on the top that appear to lock the top down in the closed position. It seems that it should use the same method to lock it when it is open. However, there doesn't seem to any mechanism that locks the prongs when the top is in the open position.

Bruce
Click to expand...

Bruce did you see the link at the top of my first post in this thread ? If so look at the 8th colour photo ( not the parts diagrams ) and you will see the metal bar in the boot compartment that the roof hooks should lock onto when the roof is stowed in the boot space , there is one each side of the boot , these mirrors the bars in the top of the windscreen for when the roof locks in its closed position ( roof up )

To me your video looks like the roof is trying to lock onto the bars but is failing and as the hook swivel to lock the roof , in its stowed position the roof is push upwards as the hooks go above the bars instead of under them .

There is a micro switch mounted just to the side of one of these boot lock bars and the wiring for that switch runs down the side of the hinge mounting and often gets chaffed through , read my original link above and I think you will find the cause of your problem .

If not send me more info .
 
I am sorry, I was skimming through several forums and I had not read your linked post.

In the pic your Torx driver is pointing at the switch that tells the car that the top is completely down. This switch was replaced (supposedly) by the dealer. I know that it's working because if I depress it the trunk lid will close onto the top. Is there another micro switch at this location?

I still don't understand how the roof hooks lock into the trunk bar. Does something move to lock the roof hooks to the trunk bars?

I need to look at the bars and see if I can tell if the hooks are riding on top of the bar instead of under the bar.

A great write up on the top mechanism. I should print it out and and give it to the techs at my dealer.

Thanks,

Bruce
 
I can reach in through the trunk pass through and should be able to feel the location of the roof hooks. I'll try it this weekend.

Bruce
 
Here's a link to a picture of the roof hook with the top down:

https://goo.gl/photos/WS9StyPFv61ArWU18

The hook is no where near the bar. Is the bar supposed to move to engage the roof hook and pull the top down?

Bruce
 
Bruce, first please remember I am no expert of these things but I have managed to solve a few members problems here with what I've learned , but in all cases I could be guessing as much as anything .

However .....logic says .. if your micro switch has been changed.... that doesn't surprise me as it's the easiest one to get to , very few tech's these days diagnose problems they just change parts until it's fixed !!!...... But if you read my original posting you will see that the wiring for this switch and much of the other roof wiring runs up the side of the main hinge mounting ( driver side for RHD cars , but could be different on a LHD car ) . The proximity of the wiring to the folding hinge is very tight and I have seen wiring including my own worn through at this point . It could be that your switch wiring or wiring in this loom is chaffed through and the folding hinge is shorting a circuit before the roof is fully down, And thus not triggering the hooks to lock onto the pins , the pins do not move . Assuming the roof panel locks onto the screen when closed you know the hooks are moving as they should and it's not the micro switches in the roof panel being faulty . Have a look and let me know if you find damaged wiring or plugs in the boot micro switch wiring harness area I mention and if that solves the issue ..... if not we may need to think again .

Boot closing is triggered by the two micro switch on the end of the boot hinge Rams , one each side but first you need to get your roof in the right locked position .

You say that if you press the micro switch to trigger it ( the one they say they changed) the boot then closes ? If you close the boot with the roof not locked down correctly and drive the car you can damage the two folding roof panels , so I would advise you don't do that .
 
Honestly ? Bruce are you actually reading what I'm bothering to write ?

The micro switch in the boot next to the locking pins is what I believe should trigger the hooks to lock onto the pins in the boot , there is also one on the top of the windscreen top edge that triggers the hooks to lock onto the top of the screen when it closes .we can assume your hooks are working correctly mechanically as you haven't said that the roof doesn't lock onto the screen when it closes, so something isn't triggering the hooks to lock when it's stowed in the boot ...so ... As I said ... check your wiring isn't damaged that feeds the micro switch in the boot first ,this wiring is next to the main ram hinge running down from the micro switch we believe isn't working correctly , you need to check this wiring area as this often gets damaged causing roof malfunctions.

If this wiring isn't damaged , then I would change the micro switch next to the pin first of all . ( I know you say it may have been changed already ) They aren't expensive and it's an easy part to change . All this info is in the linked posting I sent you originally .

If that doesn't solve it then we may have to look elsewhere for the problem .
 
The wiring looks good. It was stored this past winter so mouse damage is always a possibility but there is no evidence of mice in the car. BTW, the Z has just over 2,000 miles on the odometer.

The top will latch:

https://photos.google.com/share/AF1QipPxPvzCYcmX0SP80Of8xywxa9ttU4AEk6kQvtsxHhr8k9alTor508FI279rwV7DIw/photo/AF1QipOmD-L6XBFFeph8hYewa3NLQCmR-a9teerFKQzc?key=ZWczdF9kWEE5OGdUTnhPUHFJZkJfQlQybmk1R0lR

The switch is working and the roof hooks are working. I had to build up the switch lever with adhesive foam tape to get the roof to depress the switch to trigger the roof hooks.

When lowering the top, the roof doesn't go down far enough to trigger the roof hooks. There must be another sensor that is signalling the roof to stop short.

Bruce
 
Ok Bruce, so I need more info now we know the wiring is not damaged ( this is very common and often goes in noticed )

Some questions

1. How much did you have to build up the switch with foam , in mm's ( is the cone that triggers the switch worn or damaged ?)

2. When the roof is stowed in the boot and the boot lid doesn't close, does it close if you press and hold the close button a second time ?

3. As soon as the roof stows in the boot ( you have 5 seconds or so ) if you lift the edge of the bottom roof panel with your hand as if trying to lift it out and then drop it again does the roof lock down in the boot ?

4. When you trick the micro switch with the foam, does the complete roof mechanism then work as it should ? In other words ....Does the roof stow in the boot and the boot lid then close as if everything is ok in one movement ( or if it stops with the boot open does it close if you press and hold the button a second time ? ) If it does, does the boot lid still open from the rear for luggage access ?


There are 4 sensors and 7 micro switches in the assembly .

Micro switches

We can assume that the top section of the roof is working correctly as it latches onto the screen when closing and as you've added foam to the boot micro switch it will latch when it's stowed in the boot, this eliminates 3 micro switches , 1 in the top edge of the windscreen trim and 2 in the latch mechanism.

There are two micro switches one each side of the rear screen section , directly on the lower edge of each side of the rear screen rams ( where the rear screen lowers onto the closed boot lid) , I believe these aren't faulty as apart from the latching issue in the boot your roof otherwise works ok ? These switches are handed left and right side and aren't interchangeable .

The two remaining micro switches are on the boot hinge rams , these trigger the boot lid to close after the roof is stowed in the boot. Now I know your roof isn't locking as it should, but in my experience , I've seen this before and when the boot lid closes it triggers the roof to latch in the stowed position, so the fault could be one of these two micro switches, this is why I am asking about boot opening problems as these switches seem linked to boot opening problems . It's a game of chance with these switches , if you follow my guide in the linked post you can change these easily , it could be either switch. These switches are handed left and right side they aren't interchangeable .

Hall sensors ( these sensors are all the same part, just 4 of them )

There is 1 hall sensor in the boot, it's under a plastic trim panel that the boot partition locks down on to . This must be ok as if it wasn't the roof wouldn't work at all .

There is 1 hall sensor in the rear screen folding panel, it's located in the drivers side ( RHD car ) hydraulic ram casing , but as the rear screen panel appears to be operating as it should , I do not think this is the problem .

There are 2 hall sensors in the boot hydraulic ram , these are both in one ram , drivers side ( RHD car ), now if as I asked when the operation of roof stowage stops, if it then operates fully when you press the button a second time , it could be one of these sensors . You need will need to check the hinges/ram assembly to check which has the sensors in it , as I say it's the drivers side on a RHD car but could be different on a LHD car, but the ram with the sensors will have a lot more wiring cable tied onto it . You will need to remove the ram/hinge from its bolted position following my guide in the linked post, when the ram/hinge is free, with the ram upright with the micro switch end upper most I would try the upper sensor first , but it could be either . A tell tail sign that a sensor is faulty is that they crack around the edges , but you have to look very closely with a magnifying lense to see the cracks, but as you probably won't have to change the plugs on the hall sensors on your car ( unlike older cars ) you can remove the sensors from the rams , they just clip in and inspect them .

IMG_0322_zpsv5lexhud.jpg
IMG_0346_zpskknokjfk.jpg
IMG_0330_zps0wefnzjb.jpg
IMG_0333_zpsynoxxdj1.jpg

Cracked sensor
IMG_0344_zpshivgiaif.jpg

Again if you can answer the question I have asked , things might be clearer for me trying to solve your issue .

The sensors and switches are not expensive , in fact the most expensive is the one you said has already been changed . With the guide I have previously done you should be able to change these yourself without issue . I have changed all the sensors before, and all the switches except the switches on the rear screen panel, but they don't look difficult .

Let me know how you get on .
 
I just went out to the garage to try your suggestion #3. I cycled the roof through three cycles. It stowed correctly each time.

#1 5 mm of foam tape. The cone looks okay.

#2 Subsequent pressing does nothing although it sounds like the pump is running when the button is pressed.

#3 Could not try as top did not fail.

#4 With the foam on the switch, top stows normally with one continuous pressing of the button.

The only thing I did differently is that I used the key fob to open and close the top for the first two cycles.

Perhaps it has self corrected (wishful thinking).

Bruce
 
1.When you cycled the roof 3 times was that with the foam on the switch ?

2. Do you have any issues with boot opening to the luggage space when the roof is down ? Or window dropping or raising issues when you operate the roof ?

3. Do you have a smart top module or similar( for key operated remote opening and closing ) or is this standard on your car ? ( it's not on my previous 2009 E89 )

I've had two different cars brought to me to fix where the boot lid stayed upright after the roof stowed into the boot, both of these turned out to be cracked hall sensors, the upper of the two shown in my pictures . I would check these sensors Bruce as its looking more likely that one of these is your problem . As I mentioned before, I've seen this before and the roof isn't locking down and you naturally think this is the problem but when you change the offending hall sensors in the boot hinge the roof locks down and the boot closes as it should .
 
I've edited my post Bruce , upper sensor is the one I've changed twice .
 
I had removed the tape before I cycled the top as I wanted to try your suggestion on gently pushing the top down.

The boot opens and closes with no problems.

The windows go down and up with the top also with no problems.

Today, I tried lowering the top. It didn't work so I tried gently pushing the top. That was sufficient to enable the roof hooks to engage and complete the opening cycle. The only difference from yesterday is temperature. Yesterday was much above our normal temperature.

The remote top operation is an optional feature of the Z4 not an add on.

When I finally bring it back to the dealer, I will point them at the hall sensors.

Thank you for your help.
 
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