How to connect your Di2 system to your Windows computer

Published September 8, 2019 by BetterShifting, Last updated October 13, 2020

Modern Di2 is basically a couple of controllers and servo motors that communicate with each other using the EW-SD50 wires. Shimano lets end-users configure their own Di2 systems using their e-tube project software. This page explains how to connect your bike to your computer.


Connecting a Di2 bike to a Windows computer is done via the charging / interface port on the Junction A. Note that if your bike uses the older SM-EW67A junction then you will not be able to connect your bike using the charger.

In that case you need the SM-SM-PCE1/SM-PCE02 diagnostics device.

You probably know where the charging port is - but just in case you don't, have a look at this image:

Di2 charge and interface port

Make sure you have either the SM-PCE1/SM-PCE02 diagnostics device or the SM-BCR2 charger. Also, download an up to date version of the E-Tube Project software.

Connect instructions E-Tube

Connect using e-Tube Project

Plug your charger into the junction box and connect the other end to your computer – the order doesn’t really matter, but I tend to plug the connector into the bike first. Start the e-Tube Project software. Then just click the 'Next' button.

E-Tube Project connect

If you haven't already, the software will tell you to connect your SM-PCE1/02 or SM-BCR2.

It’ll then tell you that charging has stopped because you’ve connected the bike to the computer and started the software.

E-Tube charging stopped

Also, it will tell you to use the disconnect button when you're done and then start unit recognition.

E-Tube for Windows connecting

When the connection has been made successfully you will be show the Customize tab. This is where you can set up or tweak each component.

E-Tube Project customise screen

View installed components

Sometimes it is useful to see the list of installed components. When troubleshooting unresponsive components for example. By checking the list of installed and connected components you can figure out what part of the Di2 "circuit" is broken. Almost all components are listed on the Update tab.

E-Tube Project Update Firmware

If a component isn't listed here that means that it either isn't connected or it doesn't have any firmware that can be updated. Junction B (SM-JC41 / SM-JC40) and the external battery won't show up here for example.

Done? Use the disconnect button

When you're done please use the disconnect button as seen at the top left of the window. If you do not, the bike may not respond or may end up draining the system battery until you reconnect it. It isn't hard, but it is something to keep in mind.

Other things you can do with E-Tube Project:

Questions? Leave a comment or send me a message.