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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

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RobbiZ4
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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by RobbiZ4 » Thu Mar 17, 2022 11:28 am

Before it get's lost in the discussion section, I will place a link into this How-To section:


Link: viewtopic.php?t=129048

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Y3 Roof Diagnostic System
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E89 Roof Maintenance
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RobbiZ4
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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by RobbiZ4 » Wed Jan 18, 2023 7:37 pm

Another interesting E89 roof EKG as of today.

Continuous alerts on the dash and bongs regarding a roof issue. Unfortunately during a 400km drive. :o
There were no fault codes to find on OBD.

First of all:
The sensors in our Z4 roof have 2 valid states, HIGH or LOW, represented by ~2.0V or ~0.5V in my EKG charts. Any discrepancy indicates a (temporary or permanent) error.

EKG extract of the two microswitches coupling lock in the trunk (MS KV LI = left, MS KV RE = right):
Messung01-3_Stoerung_MS_KV_LI.jpg
Messung01-3_Stoerung_MS_KV_LI.jpg (18.69 KiB) Viewed 174 times
Unusually the "jittery" signal from the left microswitch coupling lock, represented by the green line on the chart.
The voltage of about 1.28 V on the green line is completely wrong, but the signal from the right microswitch (blue line) looks perfect. Both signals seem to change their states synchronously from LOW to HIGH or vice versa.

Switched between an external attached microswitch [left red box] and the internal microswitch of the car [right red box], the right voltage level (HIGH, LOW on the green line) deviates significantly from the norm on the left.
Messung03-3_Kontrolle_MS-KV-LI.jpg
Messung03-3_Kontrolle_MS-KV-LI.jpg (30.62 KiB) Viewed 174 times
After exchanging the two MS KV with new ones, these values were measured on the old ones:
Left: 2.49 kohms - 560 ohms => 1.282V in the non-actuated state on my EKG chart
Right 2.77 kohms - 560 ohms => 0.528V in the non-actuated state on the chart

I find it interesting and irritating, that this small resistance deviation causes such a large amount of signal distortion. So far I have no explanation for these trembling fluctuations.

But anyway, as recommended in my maintenance thread, these 2 microswitches should be replaced after 10 years to avoid exactly these surprising glitches. This Z4 was built in 2011.


⌛E89: Retractable Hardtop (roof) Maintenance (and additional) tasks
viewtopic.php?t=130932
Last edited by RobbiZ4 on Sat Jan 21, 2023 4:12 pm, edited 4 times in total.
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Y3 Roof Diagnostic System
viewtopic.php?f=23&t=129048

E89 Roof Maintenance
viewtopic.php?t=130932

About the minions
viewtopic.php?p=1861035#p1861035

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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by B21 » Wed Jan 18, 2023 11:27 pm

Seems odd that such a response comes from such a minor variation in resistance…..especially since normally resistors aren’t usually highly qualified..

Modded E89 20i MSport 2017-2022…Even more modded E89 35is 2021 onwards..details here.. https://www.dropbox.com/s/8h1vabklgzf4v ... t.pdf?dl=0


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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by RobbiZ4 » Thu Jan 19, 2023 12:02 am

B21 wrote: Wed Jan 18, 2023 11:27 pm Seems odd that such a response comes from such a minor variation in resistance…..especially since normally resistors aren’t usually highly qualified..
I agree. Maybe I'll understand it better in the near future with more tests on the input ports of the CTM.
:spy: :ant:
Y3 Roof Diagnostic System
viewtopic.php?f=23&t=129048

E89 Roof Maintenance
viewtopic.php?t=130932

About the minions
viewtopic.php?p=1861035#p1861035

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B21
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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by B21 » Thu Jan 19, 2023 2:01 pm

RobbiZ4 wrote: Thu Jan 19, 2023 12:02 am
B21 wrote: Wed Jan 18, 2023 11:27 pm Seems odd that such a response comes from such a minor variation in resistance…..especially since normally resistors aren’t usually highly qualified..
I agree. Maybe I'll understand it better in the near future with more tests on the input ports of the CTM.
Robbie....you need to get your s**t together..otherwise I might have to help you! :tumbleweed: :rofl:

Modded E89 20i MSport 2017-2022…Even more modded E89 35is 2021 onwards..details here.. https://www.dropbox.com/s/8h1vabklgzf4v ... t.pdf?dl=0


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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by enuff_zed » Thu Jan 19, 2023 2:04 pm

Robbi! I'd guess your English is at least as good if not better than mine, but I'm pretty damn sure if we ever meet and you start talking about the E89 roof I won't have a clue what you're on about.
Keep up the good work. :thumbsup:
E89 20i SDrive M Sport - mine
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RobbiZ4
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⌛Y3 Roof Diagnostic System (for all BMW convertible & roadster)

Post by RobbiZ4 » Thu Jan 19, 2023 2:45 pm

enuff_zed wrote: Thu Jan 19, 2023 2:04 pm Robbi! I'd guess your English is at least as good if not better than mine, but I'm pretty damn sure if we ever meet and you start talking about the E89 roof I won't have a clue what you're on about.
I'm pretty sure you'll understand everything. :rofl:
:spy: :ant:
Y3 Roof Diagnostic System
viewtopic.php?f=23&t=129048

E89 Roof Maintenance
viewtopic.php?t=130932

About the minions
viewtopic.php?p=1861035#p1861035

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