Strange DI2 problem

Discuss light weight issues concerning road bikes & parts.
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Posts: 146
Joined: Mon Aug 14, 2017 9:40 am

by ODC

Hello everybody,
Need advice because I am having some problems with my Dura Ace DI2 9170 group set.
The problem has happend 3 times in the past 2 weeks => 100% charged battery or enough battery percentage left over (green lamp).
Let my describe the problem. Yesterday and the other times i was riding a random gear (53/14 for example) when pushing the button to go to an other gear (53/15) my DI2 just stops working and nothing respond anymore.
The junction box which is installed around my stem doesn't show any lights anymore.
So the DI2 systeem is like totally crashed. Can't use any button of the two shifters and even the button to on the junction box doesn't work/respond.
I continue my ride and around 20 a 30 minutes later my DI2 starts working again. Green lamp on my junction box and the FD and RD are working again.

So to summarize while riding my DI2 stops working for around 30 minutes and then starts working again.

What could be the reason for my problem. I was thinking about:
- Bad battery
- Bad cable
- Bad connection
- Bad junction box
- Software bug and need to update
- ....

Any help is welcome!
Last edited by ODC on Mon Jul 16, 2018 2:29 pm, edited 2 times in total.

Posts: 18
Joined: Mon Nov 07, 2011 1:14 pm

by 1sanglier

You can check if cable is corretly install on shifter (use shimano tools to "clip" it).

by Weenie

Posts: 21
Joined: Thu Apr 12, 2018 6:43 am

by PyreofFyre


I believe that 1sanglier was referring to this tool;

[ ... -tool.html

I would also suggest connecting the bike to the PC, using the SM-BCR2 Di2 Battery Charger. Upon launching the e-tube app, you'll be able to see if all the necessary devices (derailleurs, etc) have been detected and all cables connected as required. This would rule out faulty devices/cable connections.

While in the app, it would be good to verify if the firmware for all devices have been updated.

If, after having done all these, and the problem still persists, perhaps you could borrow/buy a longer length of Di2 SD50 cable and connect that to the junction box (at one end), and connect the other end to all other devices in sequence and test for operatability. In other words, as an example, replace the existing connection to the front derailleur (on the derailleur end) with the other end of the long Di2 cable.

Hope this works.

Posts: 2
Joined: Tue Jan 22, 2019 7:04 am

by haichdot

I'm currently having this exact problem.

batter has been replaced.
All connections checked tight
Any solutions from OP?


Posts: 21
Joined: Tue Nov 06, 2018 3:16 am

by Jbass

Did you update the software and made sure you have no loose connection?

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