5 Causes Of Di2 Rear Derailleur Not Shifting & How To Fix It

If you have a bike with the di2 rear derailleur not shifting, you’d better call your mechanic and set an appointment. But what would you do if you were riding in the countryside and couldn’t find the mechanic? 

There might be a problem with the battery or connection. You probably had a crash, and your rear derailleur stopped working because of the activated crash mode. 

There are more reasons for the di2 rear derailleur not working. Read this guide to learn how to resolve these problems by yourself. Let’s get started!

5 Causes Of Di2 Rear Derailleur Not Shifting 

Why is my derailleur not shifting? There are several possible causes and solutions based on my experience. Now, I will share them with you.

#1. Outdated Firmware Version

di2 rear derailleur not shifting
Shimano Di2 9070

Shimano Di2 is an electronic technology that integrates with a mobile application. The software enables users to modify Di2 features through Bluetooth-enabled tablets and smartphones.  

So, the derailleur may not shift if you don’t update the firmware to the latest version. The new version of Shimano’s E-Tube Di2 programming app is now accessible on Android and iOS. 

#2. Out Of Battery 

A rechargeable battery powers the di2 rear derailleur. The shifting won’t work if the battery is broken or out of power. 

Some different factors can impact battery life. It may be drained by temperature, ride distance, battery age, and shift patterns.

#3. Crash Mode Is Activated

SHIMANO 105 Di2 Rear Derailleur
SHIMANO 105 Di2 Rear Derailleur

Di2 Crash Mode provides rear derailleur protection during a crash or significant impact. Once activated, the derailleur will stop shifting.

Your Shimano derailleur might stop working after a crash. You may get stressed and don’t know what to do if you’re unfamiliar with this function.

#4. Poor Connection

A poor connection might result in the di2 rear derailleur not shifting. If the connection is loose, a ton of dust will cover the surface of the junctions leading to interruptions or high resistance.

#5. Incorrect Adjustment

Your Di2 rear shifting may randomly stop working due to the incorrect adjustment. It happens mostly because you installed the electronic derailleur following how you adjusted a standard derailleur. 

There is a slight change when adjusting the limit screws. Using the limit screw, you may determine whether the chain stays on the cog or comes off when turning a half-circle. 

Overshifting and coming off can result in a crash. If it shifts into the spokes, it may damage the wheel and frame.

How To Fix A Di2 Rear Derailleur Not Working?

There are five solutions based on the causes described above.

#1. Upgrade The Firmware 


We recommend updating the firmware to the latest version. Find the most recent update on the manufacturer’s website by typing the model number of your di2 derailleur in the search box. 

Connect your bike and computer by using a USB-C cable. After that, follow the instructions to upgrade the firmware. 

#2. Charge And Replace The Battery 

It would be best to charge the battery to at least 80%. You’d better use the Shimano chargers for di2 rear derailleur batteries because they will maintain the derailleur’s activity while extending its life. 

A di2 battery may theoretically work for a run between one and three miles on a single charge. We recommend replacing the battery if it dies during the shorter distance.

Testing the battery is another way to determine if it’s time to replace it. We’ll review how to check the battery charge level and install the coin cell battery.

The E-Tube Cyclist smartphone app is one of the ways to monitor the shifter’s battery level. The other approach is to use the buttons on the shifters.

Our best choice is to utilize the buttons on the gear lever. This method lets you check the battery level in less than a second. Follow the steps below:

  1. Hold down both buttons simultaneously for roughly 0.5 seconds. If it’s green, everything is going well.
  2. However, the battery will die after approximately a month if the shifter LED goes red. If it’s your case, get a new one and swap out the battery as soon as possible.

In addition, you can download the program to utilize E-Tube Cyclist. You will proceed as follows:

  1. Press and hold the rear derailleur button for 0.5 to 2 seconds to connect to the bicycle. 
  2. The LED will blink blue to tell you that the bike is about to connect with the app.
  3. Upon successful connection, select the “Maintenance” tab. You will see your shifters’ battery level in that section.
  4. A green or red circle will show you the battery charge level. Replace your battery within a month if the circle is red.

Replace ST-R9270 / ST-R8170 shift lever battery

CR 1632 battery powers the hydraulic shifters. It may take two minutes to replace this battery easily.

  1. Pull out the lever cover on the shifter hood. 
  2. Loosen the screw with your flat-bladed screwdriver to open the battery door.
  3. Pull the battery out.
  4. Insert the new battery into the holder with the positive (+) side facing out. 
  5. Close the battery holder and tighten the screw.

Replace 105 / ST-R7170 shift lever batteries

These levers have a different battery port. It opens upward, yet not sideward. So, you must pull the front of the lever cover back to access the port. Continue the steps mentioned above!

#3. Reset The Crash Mode 

di2 rear derailleur not working
  • 10 and 11-speed Shimano Di2

To reset the crash mode, take these actions:

  1. Raise the back wheel.
  2. Press the Junction A button for five seconds. You will see a blinking red light.
  3. The rear derailleur will automatically change through all the gears as you use the pedals to reconnect the engine.
  4. Keep rotating the pedals till the derailleur finishes the shifting.
  • 12-speed Shimano Di2

In contrast to its predecessors, the 12-speed rear derailleur doesn’t require pressing the reset button. These are the steps that you need to follow:

  1. Use the shift switch to change the gear from the largest to the smallest sprocket while rotating the front chain wheel.
  2. Keep pedaling while adjusting to the largest and smallest gear. Once the Crash Mode is off, the rear derailleur will normally work.
  3. If it still doesn’t work, try disengaging the back derailleur and shifting your front one a few times before reconnecting it.

#4. Re-Insert Poor Connection

The solution is simple. Pull out each connection and re-insert it a couple of times to increase surface contact, helping to establish the connection. 

If dust accumulates on the surfaces, you might not seal the connection well enough. Seal it tightly to stop the problem. 

#5. Correct The Adjustment

Upon the proper adjustment, you can see the derailer move inwards closer to the second small gear. 

You can reverse the limit screws until there is space between them. It’s also recommended to adjust the stop to correct excessive shifting and trim. 

However, look up the manual online before working with your tool. Because there are different derailleurs, we have many ways to adjust them. 

Frequently Asked Questions

What Is Di2 On A Bike? 

Di2 is an electronic gear-shifting technology that lets riders use electronic shifters rather than mechanical shift levers. At the touch of a button, DI2 provides you with immediate, precise, and extremely quick shifts.

How Many Years Will Di2 Last? 

According to Shimano, their battery has 300 cycles of full charge. The battery will last around 11 years if charged every other week.

In this usage time, taking good care of the battery is crucial. You must keep the battery from getting too filthy and recharge it frequently.

How To Adjust The Di2 Rear Derailleur? 

  1. Put the tiny chainring on the front derailleur.
  2. Set the fifth-largest sprocket on the rear derailleur.
  3. Hold the button on your junction box until the red LED lights up. Then, you can use the buttons on the shift lever to adjust your rear derailleur.
  4. Use the X-shaped shifting button to move the rear derailleur toward the bigger sprocket.
  5. Move the rear derailleur towards the 4th biggest sprocket while cranking the front chainring until it creates a faint noise.
  6. Press the Y button four times to adjust the rear derailleur 4 steps back (towards the 11T).
  7. Press the junction box button to turn the red LED off and get out of the adjustment mode.

How Does Di2 Derailleur Work?

The Di2 derailleur is a digital integrated intelligence shifting. It gives you more control by having the rear derailleur automatically do a compensatory shift as you move the chain from one sprocket to the next.

Find out more about how the Shimano DI2 12 Speed works by watching the following video:


There are some causes of the di2 rear derailleur not shifting. It may be due to a drained battery, a poor connection, activated crash mode, an incorrect adjustment, or an out-of-date firmware version.

Do not ride the bicycle on the road until you resolve all the problems. It might malfunction at any time, which is dangerous for you. 

Now, let’s repair your di2 rear derailleur!

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