Roof Hydraulics too hot

[Wing07]

Evening all

Today was a good day until I arrived home

Fitted new alloys OEM 437M and was delighted to have no scrubbing issues on the rear end..

As a nice day been out roof up a down throughout the day but once home the roof is now stuck open with a warning on the idrive saying roof hydraulics too hot!! Nothing actually happens when I press the roof close button the windows do not go down or anything.. so now stuck with roof open.. had a search of forum but not much on the issue of hot hydraulics

Any input would be appreciated

 

[flybobbie]

First thing i would do is get to pump and feel if it's hot or still running.

 

[Wing07]

First thing i would do is get to pump and feel if it's hot or still running.

Hi the pump is cool and not running.. car cover is being utilised currently as no garage so not ideal

 

[Smartbear]

First thing i would do is get to pump and feel if it's hot or still running.

Hi the pump is cool and not running.. car cover is being utilised currently as no garage so not ideal

Water damage can cause the overheating warning, have you recently had a leak? :?
Rob

 

[Wing07]

First thing i would do is get to pump and feel if it's hot or still running.

Hi the pump is cool and not running.. car cover is being utilised currently as no garage so not ideal

Water damage can cause the overheating warning, have you recently had a leak? :?
Rob

Hi Rob

Yes water ingress has been an issue but resolved.. roof working fine throughout the day just sods law it goes when down..

I don't think it's a motor issue as the windows don't go down when the button is pressed.. if it was a motor issue I think this stage would still complete?

 

[Smartbear]

Hi the pump is cool and not running.. car cover is being utilised currently as no garage so not ideal

Water damage can cause the overheating warning, have you recently had a leak? :?
Rob

Hi Rob

Yes water ingress has been an issue but resolved.. roof working fine throughout the day just sods law it goes when down..

I don't think it's a motor issue as the windows don't go down when the button is pressed.. if it was a motor issue I think this stage would still complete?

The overheated warning could be stopping the whole process from starting despite the motor being ok, i believe the temp sensor is within the motor case. There’s a recent post on here about it.
Rob

 

[Smartbear]

Here https://z4-forum.com/forum/viewtopic.php?f=45&t=128019&hilit=Temperature+sensor
Rob

 

[Wing07]

Here https://z4-forum.com/forum/viewtopic.php?f=45&t=128019&hilit=Temperature+sensor
Rob

Cheers Rob that will be tomorrow's job might get one of those foxwells ordered aswell for future issues.

 

[flybobbie]

Didn't robbiez say the temp. sensor was a 100k thermistor.
Think he gave a part number.
Try multimeter the violet wires out of the motor, see if it's anywhere near 100k mark, open, or very low.
When i unplugged the motor plug, i couldn't move roof (expected). So the violet wires were seeing infinite resistance.
Any corrosion inside could be shorting out the temp. sensor.

 

[RobbiZ4]

Didn't robbiez say the temp. sensor was a 100k thermistor.

Yes, RobbiZ4 did this. :evil:
https://z4-forum.com/forum/viewtopic.php?p=1824163#p1824163

Try multimeter the violet wires out of the motor, see if it's anywhere near 100k mark, open, or very low.

Not korrekt:
the part to replace is a 100k one, but it's mounted in parallel to an internal 100k resistor.
You will measure sth. between 0k and 50k.
The lower this value, the hotter the pump, at least only for the CTM's logic.
Everything below 7k on the 2 violet wires is 'too hot'.

It's typicall, that after a massive water ingress these small sensors (with a glass body) inside of the pump's motor will fail.

Use thermal paste to mount a new NTC!

I don't think it's a motor issue as the windows don't go down when the button is pressed.. if it was a motor issue I think this stage would still complete?

This assumption is wrong.

 

[ph001]

“Everything below 7k on the 2 violet wires is 'too hot'.”

....can you not just snip one of the violet wires then? Or maybe it looks to see if resistance is in a certain range and also gives a fault if it’s over 50k?

 

[RobbiZ4]

“Everything below 7k on the 2 violet wires is 'too hot'.”

....can you not just snip one of the violet wires then? Or maybe it looks to see if resistance is in a certain range and also gives a fault if it’s over 50k?

Cutting the wires or replacing the NTC with a resistor bridge is not a solution.
There is a reason why the CTM checks the motor's temperature.

 

[Wing07]

Thanks for the help guys

I managed to get hold of my independent bmw specialist and will be dropping it off to him shortly. I will update thread once resolved to highlight issues that arised

Regards

Will

 

[flybobbie]

Be good if these were stuck to the motor.
https://www.ashcroft-transmissions.co.uk/temperature-strip.html
As any over temperature event would just come and possibly go.

 

[RobbiZ4]

Be good if these were stuck to the motor.
https://www.ashcroft-transmissions.co.uk/temperature-strip.html
As any over temperature event would just come and possibly go.

What should it support?

If the NTC is defective, there is no overheat in the motor, even if it got displayed on the navi.
If you cut the violet wires, who ever would have a look at this strip BEFORE he tries to move the roof?

 

[ph001]

“Everything below 7k on the 2 violet wires is 'too hot'.”

....can you not just snip one of the violet wires then? Or maybe it looks to see if resistance is in a certain range and also gives a fault if it’s over 50k?

Cutting the wires or replacing the NTC with a resistor bridge is not a solution.
There is a reason why the CTM checks the motor's temperature.

I guess the question is, who has ever had a genuine over temperature situation in this country and what would cause such an event?

 

[Smartbear]

“Everything below 7k on the 2 violet wires is 'too hot'.”

....can you not just snip one of the violet wires then? Or maybe it looks to see if resistance is in a certain range and also gives a fault if it’s over 50k?

Cutting the wires or replacing the NTC with a resistor bridge is not a solution.
There is a reason why the CTM checks the motor's temperature.

I guess the question is, who has ever had a genuine over temperature situation in this country and what would cause such an event?

Repeated use of the convertible roof can overheat the motor :?

Rob

 

[RobbiZ4]

I guess the question is, who has ever had a genuine over temperature situation in this country and what would cause such an event?

Repeated use of the convertible roof can overheat the motor :?

Yes, that's the only situation I can image: fault diagnosys and testing. The temperature is measured inside of the motor directly on the cover.


I've tested this system until it got stopped by the CTM. It took about 10-15 complete roof movements to get the temperature over the limit to open it.

The temperature monitoring is only active while an open or close process is controlled by the CTM. Unfortunately it's not monitored, when any of the two salmon relays get faulty and start the pumps motor.

 

[flybobbie]

Of course BMW could have monitored the power going to motors to cut them out if too long a period running without any button being pressed, if the relay contacts froze. Instead got to wait for over temp.

 

[RobbiZ4]

Of course BMW could have monitored the power going to motors to cut them out if too long a period running without any button being pressed...

Right.

...if the relay contacts froze. Instead got to wait for over temp.

But exactly this situation is NOT covred by BMW! The monitoring ihas been shutdown BEFORE the pump reaches it's overtemp. It will be destroyed withhin minutes. Only avoidably by regularly replacing the salmon relays.

Better solved by AUDI:
There are 2 sensor wires implemented BEHIND the 2 relays, which are going back to their CVM and monitor even the relay's behaviour.