Fix your Di2 bike

Updated October 3, 2025 by BetterShifting Terry

Has your firmware update gone wrong? Is your bike not charging? This page will get you back on the road.

The solutions to the most common Di2 issues here on this page. Have a problem that's not listed on this page? Send me an email or WhatsApp message.

Mobile app

Shifting

Batteries & Charging

  • Battery doesn't last as long as it should
  • Shifter batteries run out of charge in weeks

Connecting to your bike

Before we get started, let's quickly discuss connecting to your bike. This is useful for diagnostics and troubleshooting, and is required for a lot of the problems mentions on this page.

12-Speed Di2

If you're on 12-speed Di2 then you can connect to the bike using either the mobile app, or the SM-PCE02 interface/diagnostics tool. The latter is rather expensive (~$200) and its only use is diagnostics / updates, so most home users won't have one.

Do you have the SM-PCE02? Then the very first step is to connect that to the bike and run E-Tube Project V5 / Professional.

Don't have one? Then try to connect to the bike using the mobile app. Hold the derailleur button for 0.5 - 2s. Does that trigger connection mode (flashing blue LED)? Then go ahead and connect to the bike.

No LED activity? Try charging the bike. Does the LED light up blue? Then let it charge for a while. Is there no LED activity? Try cleaning the derailleur charging terminal using a bit of isopropyl alcohol and try again.

Still nothing? Make sure that the wire is fully plugged in at both the battery and the rear derailleur, and that there is something in the battery middle port. Also inspect the wire for damage.

11-Speed Di2

While 11-speed Di2 bikes do not come with bluetoothLE/ANT connectivity standard, almost all of them will have an internal battery. Fortunately, the battery charger for the internal battery, SM-BCR2, is also a PC-interface device.

It lets you connect you bike to a computer using E-Tube Project 4.0.4 / 3.4.5 (not V5 / Professional), and check for firmware updates, change settings, and more: Connect to 10/11-speed bikes using a Windows computer.

Besides the SM-BCR2, you can also use the SM-PCE1 / SM-PCE02 to connect to 10/11-speed bikes, and, if your bike has a D-fly installed, then you can also connect tusing the mobile app.

Problems with the Mobile App

Updated a component's firmware, and now the bike no longer works

Did your phone shut off mid-update, did your PC reboot, or did the process simply fail? Whatever the cause, the result is usually the same - the bike no longer responds to shift commands. How you go about fixing that depends on whether or not you can still connect to the bike or not.

Can't connect to the bike using the mobile app? Then try disconnecting the battery middle port. A 12-speed battery's middle port is special, and disconnecting that (taking out the wire / dummy plug) sometimes helps to get bikes back up and running,

Also, make sure that the bike is charged. Failing firmware updates can drain the battery, so it's always a good idea to give the battery a quick top up.

If this doesn't work and you do not have the SM-PCE02, then there's not much you can do at home, and I suggest you visit a friendly local bike shop to run diagnostics on the bike. The process should take about 15-20 minutes and will help to determine the next steps.

Did you manage to connect to the bike? Then take a good look at what the software is telling you. All connected components should be listed on the Update screen. If there's something missing on that page, that component isn't fully connected, or its firmware was corrupted.

If you're lucky, the software will let you rewrite the firmware to that component.

No luck? Then it's off to the bike shop next, I'm afraid.

Invalid Passkey

When you use the E-Tube Project mobile app to connect to a Di2 bike, it'll ask you to enter a passkey.

The default passkey is 000000 - six zeroes. If that doesn't work and you've tried all the obvious 6-digit combinations, then you'll need to reset the passkey. You'd need to connect to the bike using a Windows computer and E-Tube Project.

Can't connect to the bike yourself? Ask a bike shop to do it - the entire process takes about 15 minutes.

> Reset a Di2 Wireless Passkey

Can't connect to the mobile app

If you're using a valid passkey and still cannot connect to the bike, try this:

  1. Switch your phone to airplane mode
  2. Enable only bluetooth on your phone
  3. Try to connect to the bike again

And yes, I know how that sounds, but I've had multiple reports of this actually working - so give it a try.

Still can't connect? Send me a message.

Can't update 12-Speed wireless shifters

Shimano's 12-Speed semi-wireless road and gravel shifters can be updated using either the mobile app or the desktop software. If you've tried the mobile app, then you no doubt would've noticed that it won't just let you update the shifters.

In order to update 12-Speed wireless road/grx shifters, you need to connect these shifters to the rest of the bike by wire. You can connect both at the same time, or do them in turns.. that's up to you.

> Update 12-speed wireless hydraulic shifters

Error during programming when setting up derailleurs

If you're setting up your front or rear derailleur using the E-Tube Project mobile app and you're getting this message, then it probably means that the app/bike thinks your derailleur is blocked from moving. It tries to adjust the derailleur or derailleur limits and then fails.

The fix is rather simple - back off the limits a bit.

If your derailleur has limit screws (105 / GRX), then back those off first. If your derailleur has electronic limits only (Dura-Ace / Ultegra), then use the app to back those off.

Now... it may not always work. In some occasions you'll have to temporarily remove the derailleur from the bike in order to remedy this situation.

Shifting issues

I wouldn't say shifting issues are common, but chances are pretty good that you're having problems shifting, you're reading this page, after all.

Time Trial bike no longer shifts the front derailleur

Last-generation 11-speed and current 12-speed time trial bike use shifters that have just one button each, and therefore they rely on Synchronized Shift to shift the front derailleur.

Each bike has two synchro shift modes, and one manual mode. In order for the front derailleur to shift automatically as the chain reaches a certain point on the cassette, it needs to be in either shift mode 1 or shift mode 2.

Sometimes, when you change settings in the app or update components, the bike resets to manual mode. In this mode it will not shift the front derailleur automatically.

To fix this situation, cycle through the shift modes until you're back in shift mode 2. If that doesn't work, try shift mode 1.

You can cycle through the shift modes by double pressing the button on the rear derailleur (12-speed) or the one on the junction box (11-speed). The LEDs will light up, indicating the now selected shift mode:

  • LEDs on: manual mode
  • Flashing two times: Shift mode 1
  • Flashing three times: Shift mode 2

That should get your bike back up and running. Read the full guide on synchronized shift to learn more about synchro shift.

Derailleur not shifting at all

First things first - connect the charger for 5-15 minutes and try again. Even if you charged the bike yesterday, do this first.

Does the LED light up? If not, then there is a connection issue between the junction (11-speed) / rear derailleur (12-speed) and the battery.

If the LED did light up and the bike still isn't shifting, there's most likely a disconnected shifter or derailleur somewhere.

In this case I recommend connecting the bike to a Windows computer or app, and checking the list of components it detects. Is there anything missing? Then that'll tell you something about where the problem lies.

For example, if the software shows you the software, but not the derailleurs, then there is most likely a disconnected wire between the front and rear of the bike.

Is just the one derailleur missing? Then it'll either be disconnected somehow, or it's actually broken.

Derailleur sometimes not responding to button presses

Each road/gravel di2 shift lever has two main shift buttons. Behind each of those buttons is a set of two little springs.

These springs can get dislodged, or malformed, and in that case you'll find that your derailleur does not always respond to every single button press. Sometimes you have to press the button multiple times before it responds.

The fix is relatively easy, and explained by Di2 GP in the video below:

Check out his Instagram and Youtube pages for more Di2 hardware repairs, and consider buying him a coffee.

Rear derailleur in the wrong gear

If your bike is in the wrong gear, your problem is most likely one of these:

  • A 'confused' position sensor
  • or incorrect installation

Let's check the second first, because that's relatively easy to do.

Take a good look at the installation guide relevant to your rear derailleur. If your frame has a direct mount hanger installed, make sure the derailleur's B-link is not attached to the derailleur.

Also, double check that the derailleur is probably aligned to the derailleur hanger tabs. Again, take a close look at the relevant installation guide - or send me a message if you're not quite sure.

If the rear derailleur is installed correctly, then your derailleur could in fact be a couple of gears off. It happens, and usually means that the internal position sensor has become misaligned.

Is it an R8050 / R9150 or newer rear derailleur? Then you can correct this in software, using E-Tube Project version 5 and the SM-PCE02 Diagnostics Tool.

Have an older rear derailleur? Then the only way to restore its position sensor is to take the derailleur apart, correct the fault, and then seal it again. Here's a video of the Di2 GP doing just that:

Cannot shift to the smallest sprockets when in the small ring

If you've ever severely cross-chained and then tried to shift from the big to the small ring, you may have noticed that the bike shifted the rear derailleur instead.

This is called Gear Position Control, and is enabled on 11-speed Ultegra 6870 and R8050, 11-speed Dura-Ace 9070 and R9150, as well as 12-speed Dura-Ace R9200 and RX825.

Want to learn more on Gear Position Control? Read the Gear Position Control guide.

Compatibility: 10-speed, 11-speed, 12-speed

Tried all of the above and your bike still isn't working? You could be running into compatibility issues.

The main rules of Di2 compatibility are:

  • 7970 Di2 is only compatible with 7970 Di2
  • All derailleurs on a Di2 bike must be the same speed
  • All derailleurs on a Di2 bike must be the same category (MTB is one category, and road/gravel is the other)
  • 1x12 Di2 rear derailleurs are not compatible with 2x12 Di2 derailleurs