Z4 roof stuck closed. need help with MicroSwitch ohm values

[elico]

Hi Everyone. This is my first post here. Need help with my e89 roof. It is stuck in closed position

CTM was floating in water last year (not replaced. it worked after drying). A month ago the car was under heavy rain for 48 hours. after a few weeks it started to act wierd and then completely broke. no window up or down. no access to tuck.
flashing red light
Front monitor says "hardtop not latched"

I don't know if the issue is CTM or any of the Micro Switches or Hall Sensors

I removed the connectors. removed the covers and started reading ohm values

Cowl panel reached - 2700

roof package down - 2700
R Rear module closed - 550
R roof panel2 closed - 2700
L rear module closed - 550
Rear module open (hall) - 1700
L roof panel2 closed - 2700
Cowl panel released - 2700
Cowl panel locked - 550
roof package up (hall) - 1650
roof panel2 packed (hall) - 1700

Please let me know if the read values are correct for hardtop closed position (roof on).

 

[javis20]

you should get a code reader. If you have an android phone or tablet get BImmergeeks ProTool. YOu can just get the diagnostics part for $75 and a cheap ebay obd2 cable.

 

[elico]

Thank you, Javis, for the suggestion.
I have an Autel Scanner. There is no fault code.

 

[B21]

I suspect the CTM is dead…it is no more..defunct…u/s…non functioning …

 

[RobbiZ4]

You can't measure hall sensors with an ohmmeter!

They are using a current interface with 4 mA or 15 mA to signalize their states.

Pardon @B21, I won't expect a dead CTM. They hardly ever fail.

Head over to the HowTo section (just a starter for each beginner and more intelligent than posting the 100th "my roof stucks" post) and care about my recommendations, one after another. And then you will see, your roof will work great again.

 

[elico]

You can't measure hall sensors with an ohmmeter!

Let's ignore the Hall sensors and narrow it down to only micro-switches.
Compared to a good functioning E89 roof, Would you please let me know if any of the Microswitches are reporting false value.
hardtop in closed position (roof is on):


Cowl panel reached - 2700
Cowl panel released - 2700
Cowl panel locked - 550

roof package down - 2700
R Rear module closed - 550
L rear module closed - 550

R roof panel2 closed - 2700
L roof panel2 closed - 2700



Please let me know if the read values are correct for

 

[RobbiZ4]

Well, I can't commit this view as I don't narrow down to roof issues by measuring MS resistances.

The only possible statement in exact this roof position is, there is no broken wire as well as both MS pairs have a symmetric state. That may change already in the next degree, when it get's moved.

Faults in most cases are much more complex.

 

[flybobbie]

Only thing can detect with measuring resistance, i would think is open circuit if unplugged from module.
Seeing zero or resistance would only show continuity.
But in a stationary state a broken wire touching will show continuity.

It looks from earlier pictures of the inside of microswitches that there is a continuity resistor, so i would think a switch out on a table will show either 0 Ohm switched or internal resistor Ohm open (might be other way around) , value of that resistor i don't know. Compare against new switch.

Only way i could test Hall switch was 9volt battery in line with multimeter set to Ohm.
Place steel on sensor face and the current value varies.

 

[RobbiZ4]

would think is open circuit if unplugged from module.
Seeing zero or resistance would only show continuity.

No.
These switches do have an internal PCB with 2 SMD resistors on it: 570 ohms in a row, 2.2k in parallel to the internal switch.

 

[flybobbie]

would think is open circuit if unplugged from module.
Seeing zero or resistance would only show continuity.

No.
These switches do have an internal PCB with 2 SMD resistors on it: 570 ohms in a row, 2.2k in parallel to the internal switch.

Ok.
I couldn't remember what the old pictures showed other than a smd falling off.

 

[elico]

Well, I can't commit this view as I don't narrow down to roof issues by measuring MS resistances.

Please suggest how to narrow it down,

That may change already in the next degree, when it get's moved.

Nothing moves. When I press the roof open (top remove) button nothing moves. roof is completely closed, yet It says (thinks) "hardtop not latched"
Also, when I press the windows up/down switches at door panels, the windows does not move

Windows only work when I unplug the CTM

 

[RobbiZ4]

This is my way, which always displays anomalies. In addition, I'm able to replace faulty signals by correct ones towards the CTM.

Y3 Roof Diagnostic System (for all BMW convertible & roadster)
https://z4-forum.com/forum/viewtopic.php?p=1912298#p1912298

The other way is following these hints.
E89: Retractable Hardtop (roof) Maintenance (and additional) tasks
https://z4-forum.com/forum/viewtopic.php?p=1861524#p1861524

I'd suggest to get the two MS couplings replaced at first. Andy yes, that's not the easiest task as at first, you have to get the trunk frame opened. I've the required tools (INPA, Y3-Diagnostic Systems), that makes life easier.

2 salmon relays renewed?
Does the pump motor start running (I use an electronic tester to get this checked)?