An error code is the bike telling that there’s a problem that needs to be addressed. Most can be solved at home, but it might need to be seen by an expert to ensure reliable use.
Bluejay E-Bike Error Codes Explained: Bafang Motor Guide
Written by: Robbie Ferri | January 31, 2026 | Time to read 7 min
If your Bluejay e-Bike is showing an error code, don’t panic. These warnings are common on Bafang-powered bikes and often point to simple sensor or connection issues.
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.
Bluejay makes a fantastic e-Bike. Traditional styles mixed with modern technology offer something we think is very special. They are simple bikes and easy to use for any cyclist. You might sometimes see an error code on the system. This is nothing to worry about, and these codes are there to protect your bike and warn you of any issues. In this article, we will explain what the code numbers mean and how to fix each one.
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Table of Contents
Bluejay E-Bike Error Codes Explained
Do E-Bike Error Codes Mean I Need To See An E-Bike Mechanic?
Error Code 21 – Current Abnormality
Error Code 26 – Battery Voltage Too Low
Error Code 27 – Battery Voltage Too High
Error Code 22 – Throttle Error
Error Code 23 – Motor Phase Error
Error Code 24 – Motor Hall Sensor Error
Error Code 25 – Brake Sensor Error
Error Code 28 – Speed Sensor Error
Error Code 29 – Cadence Sensor Error
Error Code 30 – Communication Error
Bluejay E-Bike Error Codes Explained
Error codes are there to help you. They are a protection system for your bike, and they provide valuable data that helps you fix issues before they become bigger problems. Depending on the brand you have and the motor they use, there are different error codes.
Do E-Bike Error Codes Mean I Need To See An E-Bike Mechanic?
Error codes are a warning from the bike that something isn’t right. It could be as simple as a sensor not getting any data, a loose connector, or even a warning that the brake is being applied when starting. These are basic error codes. They let you continue riding, and it's easy to fix at home yourself.
Then we have the more worrying error codes, controller faults, internal battery problems, and even overcurrent or undervoltage. These typically require a little more attention, and the bike is designed to cut out to protect itself. This needs dealer attention.
Understanding the number means you know exactly what to do, and the bike doesn’t just get taken to a shop or scrapped. Explained error codes, like what we are providing, tell you what route you need to take next.
What Are Bluejay E-Bikes?
Bluejay is a US bike company that makes premium electric bikes. They use a traditional style but combine it with modern technology to give you the best of both worlds. These city bikes are perfect for beginners.
They use a Bafang mid-drive motor that's pedal-assist only. Most models are class one electric bikes with a top speed of 15 to 20mph when the rider is pedaling. Other Brands that use Bafang motors are Ride1Up, Aventon, and Lectric.
Bluejay E-Bike Error Codes
Now for the exciting part, let’s discuss the error codes the system can produce. We will explain what they are, why they happen, and the best way to fix them.
Error Code 21 – Current Abnormality
A current abnormality occurs when the bike's controller senses a current draw outside the required range. Typically, a wiring issue, an overloaded motor, or a controller fault.
First, we perform a power cycle, a hard restart of the system, to see if the error was just a glitch. If that doesn’t work, the connections and wires need to be checked to ensure there's no damage and that everything is connected properly. If none of these sorts the error, a dealer or e-Bike mechanic is required.
Error Code 26 – Battery Voltage Too Low
A low-voltage battery is an issue you do not want to see too often. It's where the battery is either nearing complete depletion or might need replacing. Very cold temperatures can also cause it.
Start by placing the battery in a warmer environment. Fully charge it with the manufacturer's charger. Once fully charged, get it back on the bike, and 90%, that’s the fix. Failing that, the battery will need to be inspected by a dealer or e-Bike mechanic.
Error Code 27 – Battery Voltage Too High
The opposite of the battery being too low. Too much voltage won't do us any favours either. Usually, it’s caused by a BMS battery management system fault.
Not a very easy fix, and really needs an expert's eye on it from a dealer or an e-Bike mechanic.
Error Code 22 – Throttle Error
A throttle error occurs when the throttle is sending signals to the controller that it cannot understand. A faulty throttle, damaged wiring, or a loose connector can cause this.
Most of the time, this is just a loose connector or damaged cable, so we start by checking that. If that’s not the case, then check the throttle for damage itself. It could be as simple as the handle not fully returning. If none of this works, then replace the throttle altogether.
Error Code 23 – Motor Phase Error
A motor phase error occurs when there’s a problem between the motor and the controller. These will be the wires and connectors, which are typically at fault.
Check and clean the connectors and ensure there are no bent pins or damaged cables in between. Any issues, replace faulty parts. Failing that, see an expert.
Error Code 24 – Motor Hall Sensor Error
The hall sensor sits inside the motor and helps the motor and controller understand what the rider is doing. When this goes wrong, it thinks nobody is on the bike or riding.
This is common when the motor hasn’t been serviced in a long time. Unless you can find any damaged wiring, see an expert for a service and a possible new hall sensor. Avoid opening the motor. It can be dangerous.
Error Code 25 – Brake Sensor Error
When a brake sensor comes up, it means the bike is getting a signal that the brake is on. It’s a common error and typically comes from a stick lever, connection, or cable issue.
First, check that the lever fully returns to its original position. If it doesn’t, it needs adjusting, or if you find damage, it needs replacing. If the brake unit is fine, then it will be a broken cable or a poor connection.
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Error Code 28 – Speed Sensor Error
Speed sensor errors are among the most common problems we encounter. It’s when the speed sensor cannot signal the controller that the bike is moving. It typically comes down to either a faulty speed sensor or a misaligned magnet.
Check that the magnet on the back wheel passes the sensor on the chainstay. If it doesn’t align, make it (usually 5–10 mm from the sensor). Failing that, check for damage on the wires or the sensor itself. Replace parts if required.
Error Code 29 – Cadence Sensor Error
On many Bafang setups, the cadence sensor is built into the motor. If this isn’t communicating, the bike struggles to know the pedals are moving.
This often requires the motor being opened, and we recommend it only to an expert.
Error Code 30 – Communication Error
A communication error is a broad error code that can be caused by wiring issues or a controller fault.
Check the bike's wiring and connectors for damage or water ingress. If none are found to be bad, the controller will need testing.
Display-Specific Codes
Bafang motors have different models, and sometimes they produce other codes. These are general errors and often require further investigation by an expert. On a Bluejay, there’s little chance you will see these, but just in case. Here’s what they mean.
Given that these errors are very general, here’s how we would approach them. This is to remove glitches and other sensor fault codes.
- Power off, remove battery, wait 5 minutes
- Reconnect the battery firmly.
- Check the display cable (very common issue with Bafang)
- Inspect brake sensors & speed magnet.
- Test ride in lowest assist
If this doesn’t clear the code for these errors, it’s a good idea to see an e-Bike expert or a dealer for further investigation. If you are considering a new bike, then Upway’s collection is fantastic!
Frequently Asked Questions
Why is my Bluejay e-Bike showing an error code?
Are Bluejay error codes the same as Bafang error codes?
Yes. Bluejay e-bikes use Bafang mid-drive systems, so the error codes and their meanings are standard Bafang codes found across many brands.
What is the most common Bluejay e-Bike error code?
Brake sensor errors and speed sensor errors are among the most common and are often caused by misalignment and sticky levers.
Key Takeaways
- Bluejay e-Bikes use Bafang mid-drive systems, meaning their error codes are standardized and shared across many e-bike brands and online.
- Simple issues cause most Bluejay error codes, often misaligned sensors, loose connectors, or low battery voltage, and can often be fixed at home.
- More serious error codes protect the bike from damage, and knowing what each code means helps riders decide when to take it to a dealer or e-Bike technician, rather than guessing or replacing parts unnecessarily.
