Roof fault-bong of doom

[ProfCJJ]

I got the boing and roof operation stopped halfway on way down then on way up (when I press the switch again it continues and operates correctly). Carly tells me there was a Hall Sensor on LEFT side issue. I’m going to investigate this weekend but I would bet on a similar issue - if I were a betting man of course, which I’m not,

 

[flybobbie]

Be interesting to see what you find.
I'm tempted to look at the left wires, might be preemptive strike.
Try poking the wires from inside the cabin.

 

[ProfCJJ]

I got the boing and roof operation stopped halfway on way down then on way up (when I press the switch again it continues and operates correctly). Carly tells me there was a Hall Sensor on LEFT side issue. I’m going to investigate this weekend but I would bet on a similar issue - if I were a betting man of course, which I’m not,

Well, yesterday and today I investigated this further. The errors reported were a bit confusing but always occurred at the same point when opening / closing the roof. Each time, pressing the button again allowed the process to complete.

I took out all the boot trim to get to the CTM and the connector where all the switches terminate, but I preemptively unravelled the cables on both left and right at that “bend” in the bundle to see if I had any broken / detached cables ... Sod’s law, no - all cables intact!

I then got a multimeter on the outputs of the switches at the CTM plug end - I then realised one of the Hall Sensors seemed to not be doing much with roof open or closed. I took it out, took a look at it - nothing untoward there - although there was some slight corrosion at the connector. I pulled out one of the two hall sensors I had bought pre-empting this eventuality - got a connector on the end, plugged it in, cycled the roof - worked - up and down - no errors

I neatly taped up and cable tied the cables as they were and all done.

I found an interesting table that helped me in the diagnosis- I’ll try and put a pic of it here.

Finally though - a question: when I fixed the roof I put it up and down a few times to make sure it was working consistently. What happened was that on putting the roof UP, at the point where the rear cowl lifts itself off the roof to settle back, I could hear the hydraulic pump whining but no movement for about 5 s or so, the roof then moved - albeit a bit reluctantly. I repeated the process and it did the same. I left it a few minutes and tried again and it worked fine with no hesitation ... could it have been an issue due to my operating the roof up and down perhaps a dozen times as I was manoeuvring my way around the wires and sensors??

I hope this helps someone who might be diagnosing a similar problem.

Cheers

 

[RobbiZ4]

...I could hear the hydraulic pump whining but no movement for about 5 s or so, the roof then moved - albeit a bit reluctantly. I repeated the process and it did the same...

Mostly this is reasoned by old microswitch coupling locks, which should be replaced after 10 years on both sides.

 

[JakeS76]

I've got the roof issue too. The roof went down ok today but when closing it, it stopped while the rear windscreen was still above the roof. I turned the ignition off and on, tried again and it closed completely. My fault codes are A690 Hall sensor VSW 5.1 and A6A4 Control buttons.
Do I need to get the micro switches and/or sensors replaced? Or ask the garage to check the wiring for cracks first?

 

[bigwinn]

wires2.jpg
My failed was the hall switch, which is what Foxwell reader said.
The other is microswitch.
I assume wire lengths might be different.
But why break at exact same point.
No sign of any rubbing on the other wire in each pair.
Just that the other wire was slightly longer with the twist in it.
Perhaps the twist made that wire slightly short and was being pulled when operated and just finally snapped.
But would need some pull for the insulation to go first.
I think the goo on the black tape might have made the wire insulation stiffer/brittle..

Good thread

Where are the commonest areas in the loom where cables fail?

The shell areas?
The main hinges in the boot?

Stuart

 

[RobbiZ4]

It's one single point on both sides:
the upper bow behind the rear roof shell

https://z4-forum.com/forum/viewtopic.php?p=2124235#p2124235

 

[flybobbie]

On the straight section on my car, you would think it was the bends.

 

[bigwinn]

On the straight section on my car, you would think it was the bends.

So it’s going to be a line by line check of the looms to trace this

 

[S10HSJ]

I can thoroughly recommend Mike at the Zed Shed in Warrington, for a very reasonable price he can fix the roof, I just had mine done after multiple minor fixes than didn’t solve the problem. Mine needed a complete rewire and new hoses and switches, water ingress and cheap BMW wiring that didn’t last have all been resolved. Mike really knows his work and gives warranties too. Bite the bullet and get it fixed properly I say.

 

[B21]

I can thoroughly recommend Mike at the Zed Shed in Warrington, for a very reasonable price he can fix the roof, I just had mine done after multiple minor fixes than didn’t solve the problem. Mine needed a complete rewire and new hoses and switches, water ingress and cheap BMW wiring that didn’t last have all been resolved. Mike really knows his work and gives warranties too. Bite the bullet and get it fixed properly I say.