It’s really not advised. In the long run, it will only cause more damage, and you could end up paying a very expensive bill for something that could have been avoided.
GT E-Bikes Diagnostics: Error Codes and System Warnings Explained
Written by: Robbie Ferri | January 31, 2026 | Time to read 6 min
If your GT e-Bikes suddenly show a warning or error code, it can be worrying, especially if motor assistance cuts out. The good news is that most GT e-Bike error codes are well-documented and often easy to diagnose.
More about the Author: Robbie Ferri
Robbie is a UK-based ultra cyclist, former bike shop worker, and qualified bike fitter. Deeply passionate about e-Bikes and adventure cycling, he combines hands-on experience with real-world riding to help others go further on two wheels.
GT makes an excellent electric bike, and there’s no denying, as far as performance and practically, they tick a lot of boxes. They use high-quality parts designed for longevity and an excellent user experience.
On GT bikes, you will find the technology very good and get some excellent features. One of those features is the ability to give error codes to the user to warn of potential problems. In this article, we’re going to discuss these error codes and how to use them to your advantage.
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Table of Contents
GT E-Bikes Shimano Warning Codes
Error Code E010 – System Error
Error Code E012 – Torque Sensor Error
Error Code E013 – Firmware or Drive Unit Error
Error Code E014 – Speed Sensor Error
Error Code E020 – Battery Communication Error
Error Code E021 – Unsupported Battery
Error Code E023 – Battery Electrical Protection Triggered
Error Code E024 – Battery Voltage Error
Error Code E025 – Battery Authentication Error
Error Code E050 / E05000 – Abnormal Speed Signal
GT Bosch Error Codes (Older GT Models)
When Should I Contact a GT Dealer?
What Are GT Error Codes?
Error codes are incredibly useful. They protect the bike from hurting itself, and give it the ability to tell you when it needs attention. They are a really simple system, but at times are not clear in explaining themselves.
Error Code Numbers
Error codes are not always clear and are presented as numbers. Some brands use generic error codes, while others use their own codes. GT bikes mainly use Shimano motors, so they use Shimano codes, but many older models use Bosch codes.
About GT E-Bikes
GT has been around a very long time in the bike world. From mountain biking to BMX and even road bikes, they know what makes a good bike. It started as an idea in the 1970’s by Gary Turner and continues to grow to this day with all kinds of bikes.
The electric bikes they make are mountain bikes (hardtail and full suspension) and adventure gravel bikes. Unlike many other brands, they don’t focus on commuters or hybrids. Just on and off-road fun riding machines.
GT E-Bikes Error Codes List
Now for the exciting part, let’s get into these error codes. Shimano has both warning and error codes. The error codes are the ones to worry about. The warning codes are just notifications that something might not be right. Error codes are a fault. Warning codes are a warning.
On modern GT mountain and gravel bikes, since around 2019, they use Shimano motors. On some of the very early models, they used a certain Bosch motor. Not very common but worth mentioning, these codes are listed further down.
GT E-Bikes Shimano Warning Codes
W010 – Drive Unit Overheating – Motor temperature too high
W011 – Speed Signal Not Detected – Speed sensor not reading wheel movement
W013 – Torque Sensor Not Initialised – Pedal pressure applied during startup
W020 – Battery Temperature Outside Range – Battery too hot or too cold
W10000 – Drive Unit Temperature Warning – Repeated motor overheating detected
W101 / W10100 – Speed Sensor Irregularity – Inconsistent speed readings
W103 – Torque Sensor Irregular Signal – Abnormal torque sensor readings
W106 – Temporary System Protection – Power limited to protect the system
W20000 – Battery Temperature Warning – Battery protection due to temperature
Error Code E010 – System Error
A system error means the drive unit has failed. It could be due to an internal fault or be damaged. Might even be a system glitch.
To fix this error code, start by restarting the bike. This is a full reset with the battery out for 5 minutes, then start again. If this doesn’t solve it, it needs to go to a dealer or e-Bikes mechanic.
Error Code E012 – Torque Sensor Error
This is when the torque sensor has stopped working. It often comes from a faulty sensor, or you might have been applying some pressure to the pedal when starting.
Ensure that when starting the bike, no pressure is on the pedals. Reset the bike to reset it, and if that doesn’t solve it, change the torque sensor or head to a dealer or e-Bikes mechanic.
Error Code E013 – Firmware or Drive Unit Error
A firmware or drive unit error fault can come from either the bike having damaged or incorrect firmware, or from the drive unit reading irregular data.
Often, this is more likely a glitch or a faulty sensor than a physical error. Try a power cycle full reset. If not, a dealer firmware update or reset is needed.
Error Code E014 – Speed Sensor Error
A speed sensor isn’t a big problem. It’s generally a very simple fix. Either the magnet and sensor on the rear wheel are blocked, the wiring is damaged, or it's just a bad speed sensor.
First, check that the magnet and sensor (Typically on the chainstay) are aligned and not covered in mud. Then check the wiring to and from it for any damage. If that doesn’t resolve the problem, either change the speed sensor or have someone do it for you.
Error Code E020 – Battery Communication Error
A battery communication error occurs when the battery struggles to communicate with the motor or the controller. It could be a wiring problem or maybe a faulty battery.
Start by removing the battery and charging it. Reseat the battery properly back into the bike, and this should fix the error. If not, check for poor connections and damaged wiring. Failing that, you will need the battery testing.
Error Code E021 – Unsupported Battery
This is when the system isn’t recognizing the battery. It comes from a few different places, such as an aftermarket battery being used or the battery needing dealer verification.
We recommend only using Shimano batteries. If you already are, it’s good to go to a dealer to have them verify it with the system.
Error Code E023 – Battery Electrical Protection Triggered
When this fault is triggered, the bike senses an overcurrent in the battery. It typically will switch itself off to protect the motor. Often comes from a fault in the battery.
Stop riding the bike immediately. Then fully charge the battery with the official charger. Try using the bike again, making sure not to go wild on power. If the error persists, then see a dealer or e-Bikes mechanic.
Error Code E024 – Battery Voltage Error
A battery voltage error occurs when the controller senses an abnormal voltage and stops the system to prevent damage. 90% of the time, this is a battery problem.
Fully charge the battery with the original charger. Once that's done, try it again. If it works, great. If not, it needs an inspection. We strongly avoid deep discharging the battery and letting it go to zero.
Error Code E025 – Battery Authentication Error
This is when the battery cannot communicate with the controller and the rest of the system.
Remove and reseat the battery. If you have no luck fixing the problem yourself, you need to see a dealer to have it reset by an expert.
Error Code E050 / E05000 – Abnormal Speed Signal
An abnormal speed signal error occurs when the data from the speed sensor is outside the normal range. It could be due to a wheel change, a tire size change, or a poor sensor cable.
This error requires some investigation. If you've recently changed the wheel or tire, that’s more than likely the problem. It could be that the magnet is in the wrong place. Failing that, the cable could be damaged, or the speed sensor could be broken.
Secret Shimano Dealer Codes
These codes come from the dealer level and often need a special sensor to read. If you are experiencing these, it’s important to visit a Shimano dealer to have the fault rectified properly.
- E01000 – General internal drive unit fault
- E01010 – Motor rotation abnormality
- E01020 – Torque sensor signal fault
- E01030 – Speed processing fault
- E01040 – Temperature sensor fault
- E01050 – Internal communication failure
GT Bosch Error Codes (Older GT Models)
- 410 – Control Unit Error – Button or display input fault
- 418 – Motor Temperature Warning – Drive unit overheating
- 422 – Torque Sensor Error – Abnormal pedal force signal
- 423 – Speed Sensor Missing – No wheel speed detected
- 424 – Speed Sensor Misaligned – Magnet position incorrect
- 430 – Battery Temperature Warning – Battery too hot or too cold
- 431 – Battery Communication Error – Battery not communicating with the system
- 440 – Battery Fault – Internal battery error detected
- 450 – Software Error – Firmware or compatibility issue
- 480 – Battery Voltage Error – Voltage outside normal range
- 500 – Drive Unit Error – Internal motor fault
- 503 – Battery Not Detected – Battery not seated or recognised
- 504 – Speed Sensor Error – Faulty or missing speed signal
- 510 – Torque Signal Error – Implausible torque readings
- 530 – Configuration Error – System setup or software mismatch
- 550 – Motor Temperature Sensor Error – Temperature sensor fault
- 580 – Anti-Tamper Protection – Drivetrain or system protection triggered
When Should I Contact a GT Dealer?
If you find that the error code persists, it’s important to see an expert rather than just keep resetting or ignoring it. It will only do further damage in the long run. Never work on an electric bike if you don’t know how, as the task is often complex.
Frequently Asked Questions
Can I keep riding with an error code showing?
Will disconnecting the battery reset error codes?
Yeah, a lot of errors will clear this way. They could be temporary glitches that might not return and need a reset.
Do GT e-Bikes use the same error codes as Bosch or Shimano?
GT uses both Bosch and Shimano motors, so you might have error codes from either one. In this guide, we mainly cover Shimano, as it’s the most popular, but we also mention the Bosch codes.
Key Takeaways
- Most GT warning codes come from sensors to warn you of a problem that might be occurring. Error codes indicate that something has gone wrong and needs immediate attention.
- A system reset is turning the bike on and off again will fix many faults. If they return, they need expert attention if you can’t work out why they are coming back.
- Keeping the connectors clean and checking for damage goes a long way toward preventing error codes in the long term.
