Yes, to ensure reliability, it’s good to perform regular system checks and keep firmware up to date.
Surface 604 E-Bike Error Codes: Everything You Need To Know
Written by: Robbie Ferri | January 26, 2026 | Time to read 6 min
From throttle and brake faults to battery warnings, this guide explains Surface 604 e-Bike error codes in plain English.
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.
When it comes to owning an electric bike, there are a few extra considerations you need to make compared to a regular bike. Not only do you need to understand how to remove a wheel and fix a puncture, but having the ability to read error codes goes a very long way.
An error code is a warning that something is wrong with the bike, and it needs your attention. In this article, we will explain how to interpret Surface 604 error codes and clear them. Surprisingly, most can be done from your own home.
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Table of Contents
I Have an Error Code on My Surface 604 E-Bike. Should I Worry?
Complete List of Surface 604 E-Bike Error Codes
Error Code 21 Current Abnormality
Error Code 23 Motor Phase Error
Error Code 24 Hall sensor Error
Error Code 25 Brake sensor Error
Error Code 26 Battery Undervoltage
Error Code 27 Battery Overvoltage
Error Code 28 Speed Sensor Error
Error Code 29 PAS/Cadence Sensor Error
Error Code 30 Communication Error
Error Code E01 Display Communication Error
Error Code E02 Controller Communication Error
Error Code E03 Controller Internal Fault
Error Code E04 Motor Internal Fault
Error Code E05 No Motor Output Detected
Error Code E06 Throttle Malfunction
Error Code E07 Brake Cut-Off Signal Error
Error Code E08 Sensor Communication Error
Error Code E09 Voltage Abnormal (High or Low)
What Are Surface 604 Bikes?
Surface 604 is a Canadian electric bike company that makes bikes for everyday riders. They are practical, functional, and reliable. Made for anyone from recreational cyclists, commuters, or just someone who wants to fly down a road or trail comfortably. Fat tire, commuters, city bikes, they have got them in Class 1 and Class 2!
Most of the Surface 604 range uses a Bafang Geared hub motor. It provides power directly to the rear wheel, and with 500W nominal power and 750W max power, they are not slow either. What we like about Surface 604 bikes is their ability to handle a wide range of terrain.
I Have an Error Code on My Surface 604 E-Bike. Should I Worry?
Most of the time, error codes can be fixed easily at home. There are times when you will need to be concerned and seek out a dealer for Surface 604 bikes or an electric bike mechanic. Overall, I'd say 70-80% can be fixed from home.
Complete List of Surface 604 E-Bike Error Codes
Now we are going to be discussing the error codes. Some might repeat, depending on the Bafang motor series we are discussing.
Error Code 21 – Current Abnormality
A current abnormality occurs when the current has gotten too high or too low for the bike, and it needs to shut off before it damages itself. A rare error, but common if you are on hills for a long time on full assist, or it could be an electrical fault.
Stop riding and let the battery and motor cool down for about 5 minutes, with the bike off. Once cooled down, resume riding with lower assistance. If the error persists, we recommend having it checked by a dealer or e-Bike mechanic.
Error Code 22 – Throttle Error
A throttle error indicates there’s something wrong with the throttle. This can be caused by a damaged wire, a stuck throttle, or a faulty sensor.
Quite simply, check the throttle movement and wiring. Replace anything if required, even the sensor in the worst-case scenario.
Error Code 23 – Motor Phase Error
The motor phase error occurs when one of the phase wires in the motor isn’t working as it should be. Often this is due to a faulty wire, but more than likely the connector is the problem.
In this scenario, you need to stop riding and find what’s wrong. Check the wires for any damage first, then start looking at the connectors. Unplug them and look for water ingress or damaged pins. If you cannot find any problems, then see an expert e-Bike mechanic.
Error Code 24 – Hall Sensor Error
Hall sensors provide position data in the motor. If they are not sending any data, the bike cannot work properly. Normally, it is due to cable damage or an internal motor fault.
Check the cables for any damage. If you can’t find any, it’s a good idea to see an expert for a diagnosis. Motors are not easy to open up, and they often don’t go back together very safely or easily.
Error Code 25 – Brake Sensor Error
A brake sensor error occurs when the sensor signal remains constantly on or off. It stops the bike from starting and the motor from stopping when you need it to. Often, it's because of a stuck brake lever or just a faulty sensor.
The first place you need to check is the brake levers. Ensure they have fully returned and there’s no damage to the cables anywhere. If you can’t find anything, a brake sensor will more than likely be in order.
Error Code 26 – Battery Undervoltage
An undervoltage battery can come from many sources and typically indicates that the battery isn’t providing what the motor needs. This can come from cold temperatures, a too-high load at a low charge, or dying or aging cells.
To resolve this problem, start by ensuring the battery is at room temperature. Fully charge the battery with the manufacturer's charger. Try using it again, and if the error code returns, the battery will need to be checked.
Error Code 27 – Battery Overvoltage
The opposite of an undervoltage battery is the overvoltage battery. This is when the battery is sending too much voltage to the controller and the motor. It could be due to a charging issue or a battery fault.
Disconnect the battery and let it cool down if required. Hopefully, it was only a glitch and won't come back. If so, seek expert help. Overvoltage can be really damaging to other bike components.
Error Code 28 – Speed Sensor Error
A speed sensor error occurs when the bike is not getting a signal from the speed sensor. Without this signal, we find that many bikes will not start engaging the motor. Generally, it's a misaligned magnet or a faulty speed sensor.
Check wires for any damage. Then ensure the magnet on the rear wheel is in the correct place, passing the sensor. If that fails, it’s time for a new speed sensor.
Error Code 29 – PAS / Cadence Sensor Error
A PAS (Pedal Assistance Sensor) or Cadence sensor isn’t working or sending any signals. Typically caused by a sensor misalignment or an issue with the wiring.
These sensors generally sit around the crank arms or inside the motor. If it is visible, then inspect the device and make sure it’s in the correct place on the pedal or chainstay. If not, then it will need further inspection by an expert.
Error Code 30 – Communication Error
A communication error occurs when one or more components cannot communicate with each other. Often caused by loose connectors, faulty wiring, or an issue with the controller.
Inspect all visible wiring and also connectors for any damage or water ingress. If anything is found, get it repaired. If nothing is found, it might be worth taking the controller for testing. If a newly installed component is present, update its firmware.
Error Code E01 – Display Communication Error
The controller isn’t able to communicate with the display unit. A really common error is often caused by a loose cable to the controller display or some pin damage.
Check the cables and the pins for any damage. Replace anything as required. If this fails, then it’s a good idea to consider a display replacement.
Error Code E02 – Controller Communication Error
The controller is struggling to communicate with other components. This, unlike the previous error code, means it is not two components that cannot communicate, but multiple components. Often, it is a faulty controller or wiring fault.
Check all connectors and cables when the bike is off, then restart, and hopefully it will work. If not, consider replacing the controller.
Error Code E03 – Controller Internal Fault
This means a fault has been found in the controller. Commonly due to overheating or electrical failure.
Controller replacement is often required.
Error Code E04 – Motor Internal Fault
A serious issue has been found in the motor. Anything from a faulty sensor to a breakdown can be the cause.
Do not ride. Motor inspection or replacement required.
Error Code E05 – No Motor Output Detected
This is when the controller cannot sense any feedback from the motor or detect any output. It could be as simple as a loose motor cable or as severe as a complete motor failure.
Inspect motor connections. Seek expert service if unresolved.
Error Code E06 – Throttle Malfunction
When a throttle malfunction occurs, it’s usually due to faulty wiring that keeps the throttle stuck open, a broken throttle, or wiring damage.
Before replacing, just check that the throttle returns properly. If not, a repair could be possible. Failing that, check the wiring and also consider a total throttle replacement.
Error Code E07 – Brake Cut-Off Signal Error
This is when the brake signal is constantly detected. This signal tells the motor to switch off because the user is trying to slow down. Normally, it's down to a brake lever that won't fully return or a faulty sensor.
Either change the brake sensor or find out why it doesn’t fully return. In some cases, it could be wiring damage, but that's rare.
Error Code E08 – Sensor Communication Error
Quite a general code. It means one or more of the sensors are not communicating with each other. More than likely, it's loose connectors or a sensor failure.
Inspect sensor wiring and restart the bike. It’s good to break it down sensor by sensor, checking cables too.
Error Code E09 – Voltage Abnormal (High or Low)
Abnormal voltage is a big problem on an electric bike. Too low can damage components, and too high can be even worse. This typically comes down to the battery. It could be a low charge or a battery fault.
Fully recharge the battery and avoid riding until the issue is resolved. We recommend getting the battery tested to check its health.
When to Visit a Surface 604 Certified Dealer or an E-Bike Mechanic
There are many reasons why you might want to visit a dealer or e-Bike mechanic. If you don’t feel confident you can fix the problem, you don't have the tools, or you want to leave it with an expert.
We recommend small fixes, such as inspections, maybe an odd sensor change, or even cleaning connectors you do yourself. When it comes to opening motors and controllers, going to the expert is the best option.
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Frequently Asked Questions
Are Tongsheng motors reliable?
Can I repair a Tongsheng motor myself?
Simple external repairs are straightforward to perform. Opening a battery or motor should be done only by an expert. A specialist should service bikes from brands such as Specialized or Cannondale.
Why does my Tongsheng motor overheat?
It’s not uncommon for Tongsheng motors to overheat when pushed too hard. This goes with most e-Bike systems. You need to be careful how much you push them.
Key Takeaways
- Tonsheng error codes are not uncommon and easy to understand.
- Most Tongsheng error codes can be fixed very easily.
- Maintaining your motor and regularly checking it will prolong its service life.
