Convertible top woes (has anyone not had them?!)

[octalon7]

I've had my e85 Z4MR about 3 years now, doesn't get a lot of use, but I've noticed at times when lowering the top, the drivers side latch would get slightly stuck. All I needed to do was nudge the roof and it would release smoother and close.

This week, same thing happened, but this time when the top retracted all the way the top light on the buttons continued flashing red. It would not operate after that while the light was flashing.

I put the top in manual mode and put it back up and secured it to the windscreen latches manually. That seems to reset the light, however when I try to open it now, the latch motor spins one way, then reverses briefly before stopping, still in a locked state...red flashing light returns and nothing works again.

I've read for hours on the forums, but haven't seen similar symptoms reported. Tried some simple troubleshooting:

- Rear microswitch: don't suspect this, play with the parcel shelf a few times, manually lowered and raise the roof, nothing changed. Flashing light is red not orange too, which I believe would be a stronger indicator it was this.

- Hall switches: I've not taken the top off to see the lower ones, but the one visible from the top looks visually fine, no signs of pinched wire or anything knocking it loose.

- Wiring: I've inspect portions of it, nothing obvious. Would I get a response from the latch motor if I had a broken loom somewhere?

- Top Control module: I don't think I'd get any response at all if that was it?

- Hydraulic motor: I don't think my symptoms match it? This car has low miles and garage stored, so I don't think it often would have tons of water intrusion to damage it, but it is 20 years old so I'm sure it's not in the best of shape.

- Latch motor: Does spin once I get the roof in it's locked state manually. When it's not fully closed, when I press the buttons I get no response.

- Locking latches: This is where my original symptom of the roof not opening smoothly was. Do these fail? Is the system smart enough to know? I do see they are wired and not just mechanical. So maybe?

My next step is to see if I still have my old Foxwell from prior BMW ownership and look for codes. My other generic reader doesn't see any faults. Otherwise I guess I'll be buying a new reader.

Welcome any thoughts!

[Molez93]

I'd don't have any insight here as mine has never demonstrated any issues opening or closing. I bought it new in '06. 100% garage storage for the first 10 years, now covered in my driveway during summer months. 41k miles. Been consistently cushioning the smack of the front-most part with my hand while closing, but I didn't start doing that until 8-10 years into owning it.

Edit: sorry if the second part of the title was entirely rhetorical. I figured the Internet is often consumed with people and their problems, so a post about "none" might be marginally informative to someone

[Resoelg]

Similar problem on my 2006 E85 M.
Pulling the manual cord may have caused the hydrolic release valve on the motor housing to stay open (valve stuck or manual override release wire stuck) creating the problems you are having. Pump won't move hydrolics properly since system is open so no top movement. Might be able to lubricate either cord or valve but if you are going to have to pull the pump to check it. I just ended up changing the pump and relocating....it was time. PIA!
Good luck.

[JAS1169]

I read your post. Correct me if I'm wrong. You're saying when you push top down, the front motor runs but the top does not unlock from the windshield?

If so, although the front motor is ok, a plastic gear driven by this motor has failed. Please see attached youtube

This gear may have been failing for a while and your little top pushing helped it move. However, it has now totally failed

[octalon7]

Originally Posted by JAS1169

I read your post. Correct me if I'm wrong. You're saying when you push top down, the front motor runs but the top does not unlock from the windshield?

If so, although the front motor is ok, a plastic gear driven by this motor has failed. Please see attached youtube

This gear may have been failing for a while and your little top pushing helped it move. However, it has now totally failed

Thanks for the reply! I actually watched this video when I was troubleshooting this last week. Mine does not make that sort of gear noise. It starts up, the connecting rods will rotate in the right direction for a second or two, and then it reverses for a brief second and stops working...then I get the flashing red.

It's as if it's detecting an unsafe condition to unlock the latches and just stops. I'm wondering if it's the hall sensor on the drivers latch. But yes this all started with a gradual worsening condition of the top seemingly getting a little stuck when trying to open.

[B328iC]

A long shot but here goes. In the actual latch portion to the upper windshield frame. The part that the roof latch hooks around and helps hold the roof closed. There is a part in that latch that is supposed to spin as the roof latch hooks around it. If it's rusted together it doesn't rotate as it should. This could be providing enough resistance to the mechanism to fool it into thinking the latch is stuck and it won't work properly. You need to occasionally lubricate the part so it moves freely. If it's rusted together you might be able to use something like Kroil or PB Blaster to free it up. Otherwise you might have to replace the windshield portion of the latch mechanism.

[JAS1169]

My money is still on a split plastic gear in your front motor system. This is the most common issue for the convertible top not releasing from the windshield.

The split plastic gear will start spinning but will then jam totally stopping the motor. The convertible controller will then send a signal reversing the motor and relocking the top to the windshield (this is a safety issue). The controller will then issue a red light on your system. You should have a code for this red light.

The other parts in the front windshield release are metal.

You're going to need to physical inspect the plastic gears before you can remove then as the problem.

If your inspection indicates the plastic gears are good to go, I would then focus on the white convertible controller.

[octalon7]

Originally Posted by B328iC

A long shot but here goes. In the actual latch portion to the upper windshield frame. The part that the roof latch hooks around and helps hold the roof closed. There is a part in that latch that is supposed to spin as the roof latch hooks around it. If it's rusted together it doesn't rotate as it should. This could be providing enough resistance to the mechanism to fool it into thinking the latch is stuck and it won't work properly. You need to occasionally lubricate the part so it moves freely. If it's rusted together you might be able to use something like Kroil or PB Blaster to free it up. Otherwise you might have to replace the windshield portion of the latch mechanism.

An easy check! I do believe I've fiddled around with both just to see if anything was obstructing. Put car in storage for the rainy fall, but hopefully I'll get a chance to bring it out again and can check a few more things.

[octalon7]

Originally Posted by JAS1169

My money is still on a split plastic gear in your front motor system. This is the most common issue for the convertible top not releasing from the windshield.

The split plastic gear will start spinning but will then jam totally stopping the motor. The convertible controller will then send a signal reversing the motor and relocking the top to the windshield (this is a safety issue). The controller will then issue a red light on your system. You should have a code for this red light.

The other parts in the front windshield release are metal.

You're going to need to physical inspect the plastic gears before you can remove then as the problem.

If your inspection indicates the plastic gears are good to go, I would then focus on the white convertible controller.

Much appreciated. If the plastic gears are toast, would I still be able to manually open and close it using an allen key? I'd think it would still use the same gears to turn?

[JAS1169]

I already posted a youtube video, open it and go to about 1:40 and you'll see the guy in the video hand cranking the top open.

Look I totally agree with you with your question how do I manually release the top if the release gears are gone. Basically, you're going to have to work at it.

However, by manually opening the top you just might confirm that the gears are shot. In that, the gear box have rods that go to the right and left hooks. These rods should spin as you turn the key, if they spin while you're turning then it's working. However, if those rods start sort of skipping or binding up then you just confirmed the gears are gone.

This takes a long time and a lot of hand cranking.

[octalon7]

Originally Posted by JAS1169

I already posted a youtube video, open it and go to about 1:40 and you'll see the guy in the video hand cranking the top open.

Look I totally agree with you with your question how do I manually release the top if the release gears are gone. Basically, you're going to have to work at it.

However, by manually opening the top you just might confirm that the gears are shot. In that, the gear box have rods that go to the right and left hooks. These rods should spin as you turn the key, if they spin while you're turning then it's working. However, if those rods start sort of skipping or binding up then you just confirmed the gears are gone.

This takes a long time and a lot of hand cranking.

Yeah, I've done it a half a dozen times, it's smooth when using an allen. Takes a while of course, but seems to operate just fine. The video only briefly shows the manual use, but doesn't mention any noticeable noises or issues, so it had me wondering. I imagine it's possible there's a gear just tied to the electric motor in there too.

Even when it was working for the most part, something wasn't fully operating before the module called for the hydraulic pump to start pulling the top back. That or maybe my hydraulic lift arms are shimmed incorrectly and the top itself isn't lined up properly.

[JAS1169]

No, the gears are the same for motor driven and manual.

I still believe it's more than likely a split gear only because it's the most common cause for your issue. However, you saying the manual system was smooth and worked well caused me to wonder if it might be something else. Have you put a code reader on the car, you'll need a code reader that does BMW convertible top error codes. The codes might involve the wiring harness to the front sensors. However, you also might get something like can't reach convertible controller.

Were the hinge lifters removed, rebuilt and then reinstalled? If, yes, then I honestly don't have a clue. However, I think it would really have to be way out of alignment to cause this issue. (did the car ever receive some kind of body damage?)

When you say " something wasn't fully operating before the module called for the hydraulic pump to start pulling the top back" it sort of points to a convertible controller issue. The code reader may or may not confirm this.

Here's what I would do if the code reader does not provide any good leads. I would pull the front motor with its attached gear box and check both sides of the gears. If bad, I'd get a new motor with attached gear box. If the gears are good, I'd simply reinstall and focus on the convertible controller.

[octalon7]

Originally Posted by JAS1169

No, the gears are the same for motor driven and manual.

I still believe it's more than likely a split gear only because it's the most common cause for your issue. However, you saying the manual system was smooth and worked well caused me to wonder if it might be something else. Have you put a code reader on the car, you'll need a code reader that does BMW convertible top error codes. The codes might involve the wiring harness to the front sensors. However, you also might get something like can't reach convertible controller.

Were the hinge lifters removed, rebuilt and then reinstalled? If, yes, then I honestly don't have a clue. However, I think it would really have to be way out of alignment to cause this issue. (did the car ever receive some kind of body damage?)

When you say " something wasn't fully operating before the module called for the hydraulic pump to start pulling the top back" it sort of points to a convertible controller issue. The code reader may or may not confirm this.

Here's what I would do if the code reader does not provide any good leads. I would pull the front motor with its attached gear box and check both sides of the gears. If bad, I'd get a new motor with attached gear box. If the gears are good, I'd simply reinstall and focus on the convertible controller.

Great, really appreciate the thoughts. I purchased a code reader tonight. I'm about to head out of town so I'll pull the codes next week.

As for the condition of the car, it's been fairly well taken care of, but I am the 4th or 5th owner and I only have paper records dating back for the past 2 owners. It's a fairly low mileage car, under 60k. Doesn't mean the top wasn't worked on at some point though, just not under my ownership.

[Phillies8008]

With a lot of these plastic parts it's more about age than miles. These cars are getting to the point where plastic breaks down and/or becomes brittle regardless of usage.

Related, but different: when my house was built about 25 years ago, it was plumbed with CPVC pipes. Guess what becomes very brittle after about 20 years or so? If you guessed CPVC pipes, gold star for you. If you touched them at all, they'd burst; after the third time I was done with it and had it all ripped out in favor of PEX which, I assure you, was neither fun nor cheap. Hopefully that'll last much longer than CPVC, but in any event it's very unlikely that I'll still own the house.

[octalon7]

Originally Posted by B328iC

A long shot but here goes. In the actual latch portion to the upper windshield frame. The part that the roof latch hooks around and helps hold the roof closed. There is a part in that latch that is supposed to spin as the roof latch hooks around it. If it's rusted together it doesn't rotate as it should. This could be providing enough resistance to the mechanism to fool it into thinking the latch is stuck and it won't work properly. You need to occasionally lubricate the part so it moves freely. If it's rusted together you might be able to use something like Kroil or PB Blaster to free it up. Otherwise you might have to replace the windshield portion of the latch mechanism.

Pulled the car out of storage, still spinning nicely. I had thought this originally that something was causing the latch to get caught but I checked the latches and they spin.

[octalon7]

I picked up a Foxwell NT510 code reader last night and ran the top codes:

43/44: CVM: Drive, cowl panel, open circuit
40/41: CVM: Drive, cowl panel, current too high when closing safety catch

This time around when I had the code reader attached the top did it's thing where it starts to spin one way, but then stopped and starts reversing for a brief second. However the red warning light did not stay blinking. So it's not throwing a code this time and it still lets my try to open and close using the buttons. It won't unlatch though. I also noticed it does not crack the windows down as it normally would.

Update: Now I have no longer have response at all from the buttons and no lights. Same codes showing in the CVM as before.

[JAS1169]

well, here is google answer:

The "40/41 CVM: Drive, cowl panel, current too high when closing safety catch" error indicates a mechanical or electrical issue with the convertible top's cowl panel locking system, often caused by a short circuit or a binding component. Solutions include lubricating the latch mechanisms, checking for obstructions or damage in the wiring and sensors, ensuring connections are secure, and potentially replacing the convertible top motor or wiring harness.
Possible Causes
Mechanical Obstruction: The top might be binding or misaligned, causing the motor to draw too much current when trying to close.
Wiring Issue: A short circuit in the wiring to the cowl panel lock motor or its associated sensors can trigger this fault.
Sensor Malfunction: Damaged or faulty sensors in the locking mechanism can send incorrect signals, leading to the error.
Component Failure: A failing convertible top controller or the latch motor itself could be the source of the problem.
Troubleshooting Steps
Lubricate Latches: Apply a suitable lubricant to the cowl panel latch mechanisms to ensure they are operating smoothly.
Inspect for Obstructions: Manually check the cowl panel and related components for any physical obstructions or damage.
Check Wiring: Inspect the wiring harness to the front latch motor and sensors for signs of damage, such as broken wires or loose connections.
Clean Connectors: Use an electrical contact cleaner to clean any male/female electrical connectors related to the roof system.
Check Fuses: Locate and inspect all fuses related to the convertible top system to ensure none are blown.
Test Operation: Try to cycle the roof open and then closed again, paying close attention to how the cowl panel engages. Sometimes, manually pushing the top forward during the closing sequence can help the system catch.
Scan with BMW Software: If the issue persists, use a scanner with proper BMW software to read and clear fault codes from the soft top module, which may provide more specific information.

[octalon7]

Originally Posted by JAS1169

well, here is google answer:

The "40/41 CVM: Drive, cowl panel, current too high when closing safety catch" error indicates a mechanical or electrical issue with the convertible top's cowl panel locking system, often caused by a short circuit or a binding component. Solutions include lubricating the latch mechanisms, checking for obstructions or damage in the wiring and sensors, ensuring connections are secure, and potentially replacing the convertible top motor or wiring harness.
Possible Causes
Mechanical Obstruction: The top might be binding or misaligned, causing the motor to draw too much current when trying to close.
Wiring Issue: A short circuit in the wiring to the cowl panel lock motor or its associated sensors can trigger this fault.
Sensor Malfunction: Damaged or faulty sensors in the locking mechanism can send incorrect signals, leading to the error.
Component Failure: A failing convertible top controller or the latch motor itself could be the source of the problem.
Troubleshooting Steps
Lubricate Latches: Apply a suitable lubricant to the cowl panel latch mechanisms to ensure they are operating smoothly.
Inspect for Obstructions: Manually check the cowl panel and related components for any physical obstructions or damage.
Check Wiring: Inspect the wiring harness to the front latch motor and sensors for signs of damage, such as broken wires or loose connections.
Clean Connectors: Use an electrical contact cleaner to clean any male/female electrical connectors related to the roof system.
Check Fuses: Locate and inspect all fuses related to the convertible top system to ensure none are blown.
Test Operation: Try to cycle the roof open and then closed again, paying close attention to how the cowl panel engages. Sometimes, manually pushing the top forward during the closing sequence can help the system catch.
Scan with BMW Software: If the issue persists, use a scanner with proper BMW software to read and clear fault codes from the soft top module, which may provide more specific information.

Here's what I found this evening.

I disconnected the battery for 15 minutes, no change in behavior.

The top buttons are no longer displaying LEDs, even when pressed and they start to engage the motor.

The top buttons will start to engage the top latch motor, only if I manually close the top completely. If it's not entirely closed, the buttons are dead.

If the top is closed and I hit the button to close it, the top motor starts the sequence to open the top. Odd, that's backwards. If the top is manually closed and I use the button to open it, the top motor starts to open the latches, pauses, reverses for a short second and then the buttons cease operation completely until I again close the top manually all the way.

I cleared the top codes, 40/41 cleared, but 43/44 remained.

I think I need to inspect the wiring next. If ok, sounds like could be the top module, latch motor, latch, or even the top controller switch? Based on google and a troubleshooting table I've seen posted a few spots.

[JAS1169]

Here's what I found this evening.

I disconnected the battery for 15 minutes, no change in behavior.

The top buttons are no longer displaying LEDs, even when pressed and they start to engage the motor.

The top buttons will start to engage the top latch motor, only if I manually close the top completely. If it's not entirely closed, the buttons are dead.

If the top is closed and I hit the button to close it, the top motor starts the sequence to open the top. Odd, that's backwards. If the top is manually closed and I use the button to open it, the top motor starts to open the latches, pauses, reverses for a short second and then the buttons cease operation completely until I again close the top manually all the way.

I cleared the top codes, 40/41 cleared, but 43/44 remained.

I think I need to inspect the wiring next. If ok, sounds like could be the top module, latch motor, latch, or even the top controller switch? Based on google and a troubleshooting table I've seen posted a few spots.

Ok, based on the above, the sensors do not know the position of the top. This could be caused by a break in the wiring Harnes to the sensors from the white convertible controller. So, based on your info it's the controller or the Harnes.

[octalon7]

Originally Posted by JAS1169

Ok, based on the above, the sensors do not know the position of the top. This could be caused by a break in the wiring Harnes to the sensors from the white convertible controller. So, based on your info it's the controller or the Harnes.

Yeah, sure seems like it. I'm still wondering what would have caused the original behavior, which was a latch that seemed to get slightly stuck. Maybe it's unrelated issue.

I'm about to head out of town. I may just buy a used controller, looks to be all sorts of salvaged ones on ebay and swap it, just to see if any behavior changes. Thinking that might be a quicker step than pulling everything else apart to trace wires. If it's the same, then I guess the wires are likely it. I've read lots of different accounts on whether the controllers need to be programmed for the car (not something I can do AFAIK). Many posts say yes, and then others say no that they have swapped them without an issue. Not sure why there are different experiences.

[octalon7]

I think I've had success!

I purchased a used controller off Ebay for a very fair price (~$40 USD). Just swapped and my top came back to life! Interestingly enough, the seller said the part was from a 2003, and my car is a 2006, however the module was labeled with v4 HW and SW and my old one was v3. Of course there's a chance mine was replaced in the past as I'm not the original car owner, or the one on that parts car was replaced before as well.

I didn't play around with it too much, so knocking on wood this will be the trick for a while.

Thanks for helping me walk through it!

[JAS1169]

Well, glad to see it work out.