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Unanswered Bosch display and motor problem.

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pottert247

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I have a cube ebike with a purion display. My battery is fully charged and clicked into place. When I hit the power on button the display turns on for a split second then switches off. When this happens I can hear a quick “wuuuurrr” from the motor.

Any suggestion on how to keep it “wuuuuring” with the display staying on so that I can ride it?

Thanks in advance
 
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check to see your battery connection is not loose and clean the battery contacts. Also check the cable connection to the purion.
 
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Mikerb said:
check to see your battery connection is not loose and clean the battery contacts. Also check the cable connection to the purion.
Click to expand...

Thanks for your response Mikerb

Yep checked all the connections I can see without taking the motor off and all contact points are clean. It’s strange because it’s getting power because it consistently turns on for a split second but feels like it has a failsafe to just switch off instantly if something isn’t right.
 
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Try switching the bike on by using the battery on/off button. Dont know about your bike but some have a small hole that gives you access to that button using something like an allen key.
 
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If you haven’t already, it might be worth checking the connection between the display and motor. I’ve know crud to get inside the casing, if moisture has got in there, there could be some corrosion across the contacts.
 
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Hi,
I have just started to get the same problem.
Power the controller on, motor wuuuuurs for a second then the whole thing powers off. The duration of the wurrrr gets shorter and shorter each time I repeat it (say 10 secs between) . If I let it rest/remove battery then try again, the cycle repeats.
Is this what you were seeing?
I wonder why software needs upgrading? Surely this would be a known issue.
Looks like I'm going to strip it all down a look for water/bad contacts etc...
 
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marks123 said:
Hi,
I have just started to get the same problem.
Power the controller on, motor wuuuuurs for a second then the whole thing powers off. The duration of the wurrrr gets shorter and shorter each time I repeat it (say 10 secs between) . If I let it rest/remove battery then try again, the cycle repeats.
Is this what you were seeing?
I wonder why software needs upgrading? Surely this would be a known issue.
Looks like I'm going to strip it all down a look for water/bad contacts etc...
Click to expand...
A LBS will always update firmware to the latest release when they hook up to the Bosch website. That was nothing to do with the OPs issue. His issue was a misaligned speed sensor magnet. The bike does a start up routine when it is powered on, sending a signal to each component required for the bike to operate, and expecting a confirmation signal from each. If one of those component does not return the signal the bike powers off. The components required for the bike to operate are speed sensor, torque sensor, battery and motor. The speed sensor is the most prone to failure usually due to cable damage or misalignment between magnet and sensor. Other than that all you can do is check the connections at the motor and on the purion.

What bike is it?
 
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I have just upgraded my rear brake on a Trek Powerfly 4, bit of hassle to remove the battery mount to route the new brake line, but overall no big deal.
So I get it all back together but before I reinstall the rear wheel and take it off the stand I turn the display on, nothing.
Question is does the rear wheel need to be in for the system to fire up?
I have back tracked all my work and there is no visually damaged wires or obvious issues.
Battery has been out of the bike for a few days and I read that this can cause a delay to the electrics firing up.
Thoughts please.
 
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Mikerb said:
A LBS will always update firmware to the latest release when they hook up to the Bosch website. That was nothing to do with the OPs issue. His issue was a misaligned speed sensor magnet. The bike does a start up routine when it is powered on, sending a signal to each component required for the bike to operate, and expecting a confirmation signal from each. If one of those component does not return the signal the bike powers off. The components required for the bike to operate are speed sensor, torque sensor, battery and motor. The speed sensor is the most prone to failure usually due to cable damage or misalignment between magnet and sensor. Other than that all you can do is check the connections at the motor and on the purion.

What bike is it?
Click to expand...
I don't think the speed sensor will be checked at startup, the sensor is a reed contact, this means the circuit is normally open, until closed by the magnet.
 
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All4Fun said:
I don't think the speed sensor will be checked at startup, the sensor is a reed contact, this means the circuit is normally open, until closed by the magnet.
Click to expand...
the sensor is connected to the CAN..otherwise it would not be a ble to send its data. A start up routine would request a "hello" from the sensor.
 
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Wodger63 said:
I have just upgraded my rear brake on a Trek Powerfly 4, bit of hassle to remove the battery mount to route the new brake line, but overall no big deal.
So I get it all back together but before I reinstall the rear wheel and take it off the stand I turn the display on, nothing.
Question is does the rear wheel need to be in for the system to fire up?
I have back tracked all my work and there is no visually damaged wires or obvious issues.
Battery has been out of the bike for a few days and I read that this can cause a delay to the electrics firing up.
Thoughts please.
Click to expand...
No...............if the bike does not power on then it is not seeing the battery and since you removed the battery mount I would think the most likely cause is the connection between the battery and the plug it connects to. ....or possible one of the connections on that plug.
 
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Mikerb said:
No...............if the bike does not power on then it is not seeing the battery and since you removed the battery mount I would think the most likely cause is the connection between the battery and the plug it connects to. ....or possible one of the connections on that plug.
Click to expand...
Just an update on this,
As I had no idea what was going on with the power issue I completed my brake install yesterday so the bike was back together.
Sent an enquiry off to Bosch, no reply yet.
I had put the bike on the charger 2 days ago but that made no difference, the same as replacing batteries in the display had no effect.
Then this morning day 3, I when out the shed, hit the power and it all fires up like nothing had happened.
I hadn't changed anything, wriggled any wires, except for setting the ergonomics of the new brake MC and Purion display on the bars, nothing.
Yesterday I did however ride the bike up and down the street bedding in the new pads, as I thought it could do no harm I also held the power button on a couple of times thinking the wheel sensor might trigger something, at the time nothing happened.
Anyway I'm a happy camper now my bike is fully functional, I was pretty confident that I hadn't done any damage during the brake install.
I should add before all this happened, I got a puncture 25 klms from home, no big deal as I always carry a couple of tubes.
Long story short, both my spare tubes would not inflate and I pushed the bike 10 klms without the power on until my girlfriend arrived to pick me up.
I wouldn't have thought that it would make a difference but it completes the story of how I got to where I was, coincidence, make you're onw decision.
Maybe this post will help someone else in the future.
 
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Just experiencing the same issue!!! spent the morning putting on new tyers and tubeless, charged up the battery and when I went to switch it on it just switches off with a little whirr! Have checked all the wiring and also done a battery reset but nothing.
 
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