Bosch Troubleshooting!

Benlingwood

Finding my (electric) wheels
Sep 17, 2025
6
1
Hello all! New member here... I have a weird issue with one of our electric bikes.. It has a Bosch Purion Display/Control unit that refuses to turn on the bike. Manually turning on from the battery works, and the display lights up and works as normal including turning off the system... But it will not turn on the bike which is very frustrating. I work on a very remote island and have around 10 e bikes running the same system, i cannot rely on guests to pull the battery cover off the frame to turn the bike on each time so i am hoping someone here may be able to advise. I have tried a brand new spare control unit here and it has the exact same issue... Is this battery related, motor? I took the entire motor and battery out cleaned contacts, checked the wiring & tried new battery's but it has left me stumped.

Look forward to hearing some wisdom!
Many thanks,
Ben
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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If you have identical bikes then straightforward to fault find by swapping parts over until the problem moves to the other bike.

Every wire, every connector, if the display is removable then its mount and contacts, all are part of the system.
 
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Benlingwood

Finding my (electric) wheels
Sep 17, 2025
6
1
I have just tried the brand new control unit on another bike, it appears to be the an issue with the purion display... weird! Is it maybe a software issue?
 

cyclebuddy

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Nov 2, 2016
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I have just tried the brand new control unit on another bike, it appears to be the an issue with the purion display... weird! Is it maybe a software issue?
Maybe?
 
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cyclebuddy

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Nov 2, 2016
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I wish it was as simple as that!
Then you'll probably need a dealer with the CANbus diagnostics software. Probably not easy to find on a "very remote island".
 

Benlingwood

Finding my (electric) wheels
Sep 17, 2025
6
1
Then you'll probably need a dealer with the CANbus diagnostics software. Probably not easy to find on a "very remote island".
Yeah a boat journey plus 200 miles driving to the nearest Bosch tech, due to expand the fleet the start of next definitely wont be buying anymore Bosch system bikes since they make it so hard to repair.
 
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saneagle

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Oct 10, 2010
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Yeah a boat journey plus 200 miles driving to the nearest Bosch tech, due to expand the fleet the start of next definitely wont be buying anymore Bosch system bikes since they make it so hard to repair.
Self-repair of the electrical system is not possible with these type of bikes. If you want self-repair, you have to get simple Chinese ones or convert bikes to electric yourself.
 

Nealh

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One will say not just Bosh , any propriatary brand that utilises locked in systems . So Yamaha, Steps , Giant etc,etc.
As already mentioned if one wants self repair/diagnosed system then generic China stuff or kits.
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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UK bike hire business model is generally to keep bikes only for the warranty period to cover all repair issues, match fleet size to market size well enough to achieve high utilisation, and sell bikes at a substantial discount to new RRP to recoup quite a bit of the investment.

With hire rates around £50 to £70 per day, it works pretty well. But different in your remote location!
 

Benlingwood

Finding my (electric) wheels
Sep 17, 2025
6
1
UK bike hire business model is generally to keep bikes only for the warranty period to cover all repair issues, match fleet size to market size well enough to achieve high utilisation, and sell bikes at a substantial discount to new RRP to recoup quite a bit of the investment.

With hire rates around £50 to £70 per day, it works pretty well. But different in your remote location!
I work on a private island these are our island bikes they are not hired out but used by various people every week, we are very eco conscious so not turning over bikes every year just for warranty purposes.
 

Benlingwood

Finding my (electric) wheels
Sep 17, 2025
6
1
One will say not just Bosh , any propriatary brand that utilises locked in systems . So Yamaha, Steps , Giant etc,etc.
As already mentioned if one wants self repair/diagnosed system then generic China stuff or kits.
As far as I can see you can buy the steps diagnostic hardware for a couple hundred quid quite easily, Bosch on the other hand is a different story!
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
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As far as I can see you can buy the steps diagnostic hardware for a couple hundred quid quite easily, Bosch on the other hand is a different story!
You can do the Bosch training course, like I did, then you can buy the necessary dongle and link to their software. IIRC, the training was in Lemmington Spa or somewhere around there, so if ever you go down that way, you should get booked in. It doesn't cost much. I think I paid about £45.
 

soundwave

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May 23, 2015
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