Bosch engine not engaging

Weons

New Member
Hi there!

I've got a Batavus Ebike with a bosch active line engine (more details below). The display registers the current battery charge and the current speed when pedaling, but the engine does not engage even though everything seems like it should be working.

Specifications:
Batavus Milano E-go 2015
Bosch Active line - 0 275 007 032
Bosch display - 12700 020 906
Bosch battery 400w - 0 275 007 514

Problem solving:
Battery is charged
Display registers battery charge
Display registers current speed
Display changes mode and reacts to handlebar remote
Engine reacts and runs when "Walk" button is pressed on handlebar remote
Contacts between display and bike display holder have been cleaned
Battery has been soft-reset by holding the power button for 30 secs

I really don't understand why the engine does not engage when it should. The display registers the speed and the engine works with the "Walk" button. The battery works and I've cleaned the contact points of the display.
I have no yet opened the engine itself to give it a cleaning, but since the engine works with the "Walk" button, it doesn't seem like the problem lies there?

Does anyone have any idea of what might be wrong? My logic tells me that the signal from the display to the engine, telling it to engage, is getting lost somewhere. Or maybe the engine doesn't register the crank turning at all, but I don't know how to test for this.
 

William - Bosch Team

Active Member
Hello Weons!

It is not recommended to open the Drive Unit. There are no serviceable parts inside. Additionally, some of the Drive Units require a special factory fixture for proper re-assembly.

The fact that you get a speed display and functional Walk-Assist makes this a tough one. The display does not send a signal to the DU to trigger assistance, this is done by sensors in the DU. The Display DOES allow selection of assistance mode, but this is different.

Are you able to select an assistance mode?

Are you able to take the eBike to a Certified Bosch Dealer? They can likely check for error codes and create a Diagnostic Report.
 

m.g.380

New Member
Hi Weons
I have a new trek rail 9 with the Bosch cx motor that is doing the exact same thing.
I’ve taken it to the bike shop and talking to the mechanic and he didn’t quite get it, all he could think of was the rear wheel speed sensor. This explanation made now sense to me as the speed was working. I was thinking something more like a torque sensor or cadence sensor. It just seems to not be picking up rider input into the pedals.
Have you had a resolution with your bike? I would be really interested to find out, because I’m not very confident in the bike shop.
 

William - Bosch Team

Active Member
Hi Weons
I have a new trek rail 9 with the Bosch cx motor that is doing the exact same thing.
I’ve taken it to the bike shop and talking to the mechanic and he didn’t quite get it, all he could think of was the rear wheel speed sensor. This explanation made now sense to me as the speed was working. I was thinking something more like a torque sensor or cadence sensor. It just seems to not be picking up rider input into the pedals.
Have you had a resolution with your bike? I would be really interested to find out, because I’m not very confident in the bike shop.
Was your mechanic able to save a Diagnostic Report using the Bosch software? Both of these issues are a bit unusual, and error codes might be very helpful in solving.
 

m.g.380

New Member
Was your mechanic able to save a Diagnostic Report using the Bosch software? Both of these issues are a bit unusual, and error codes might be very helpful in solving.
Hi William

there were no error codes that come up when the fault occurs, and from what I’ve been told from the mechanic, there are no faults when they’ve plugged the bike into their diagnostic machine.
the fault randomly occurs and has happened to me about 4-5 different times. The first time was 4 days from new. Bike is less then 3 weeks old. It literally feels as if there’s no input being registered whilst everything else is working perfect.
 

William - Bosch Team

Active Member
Does this happen sporadically for short periods while already riding at speed, or does it happen also when starting from a stop?

Some error codes do not show up on the display while riding. Best practice is to "save" a diagnostic report so it can be viewed in its entirety as a PDF, or at least view all 3+ tabs in the diagnostic software. Error codes may show up in 1 or more of 3+ tabs. Sometimes, shops don't know to click through and check each tab.

You mentioned that you are not very confident in the shop. Is it possible to take it to another one that may be more familiar with the Bosch System?
 
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m.g.380

New Member
Does this happen sporadically for short periods while already riding at speed, or does it happen also when starting from a stop?

Some error codes do not show up on the display while riding. Best practice is to "save" a diagnostic report so it can be viewed in its entirety as a PDF, or at least view all 3+ tabs in the diagnostic software. Error codes may show up in 1 or more of 3+ tabs. Sometimes, shops don't know to click through and check each tab.

You mentioned that you are not very confident in the shop. Is it possible to take it to another one that may be more familiar with the Bosch System?
Hi William
The problem occurs at random times eg. First time it happened was after a long down hill flow tracks with large jumps, where I was over the 25km/h speed limit the whole way, and when I started to pedal after the track was finished there was no motor. Turned bike off/on a few times eventually came good sort of, the motor also gives max power straight away with little input when it starts to work each time.
next time was pedalling up a long Fire rd, got to the top then it just stopped, I done the same off/on routine as the last time and had same result. And the last time it happed was similar pedalling up a fire rd, then no motor. Couldn’t get it to work after that one for a couple of hours. Then took it to bike shop. The issue happens at different times in the ride, could be 1/2 hour in, could be 2km in.
The bike shop couldn’t fault it unsurprisingly seems it was working fine when it went in. I have it back now and rode it yesterday with no issue.
I’ll ask another bike shop if they know anything about it, but it’s unlikely. Also they’ll probably charge me for the privilege of putting a 3 week old bike on their diagnostics machine.
The next time it happens will be the last for me unfortunately. Unreliability is my number one hate. I’ll be aiming for a refund.
 

William - Bosch Team

Active Member
I'll share this info with a colleague in your area, and see if they have any region-specific service recomendations.

If your shop did not already call the Bosch eBike Service hotline, I'd recommend they try that. The technical reps on the phone can generally be a bit more effective in helping to diagnose issues remotely, vs purely text/internet based. They can also look at the diagnostic report PDF and get a better idea of what is going on, even without error codes present. If you have a copy of the report, I'm happy to view it via PM, but a call from your shop to Bosch Service is the best option.

Very sorry you are having this issue with a new bike. Fortunately there are not that many Bosch components on there, so once the root cause is identified it should hopefully be a straightforward fix.