Yes, to ensure reliability, it’s good to perform regular system checks and keep firmware up to date.
Tongsheng Error Codes: How To Remove Them
Written by: Robbie Ferri | January 30, 2026 | Time to read 6 min
Seeing a Tongsheng error code on your e-Bike display? Here’s exactly what it means and what to do next.
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.
Modern cycling has changed since the rise of e-Bikes. The technology is very impressive, and we are getting bikes that not only let us go farther and faster but also alert us to issues. These are the error codes, and understanding them is essential to your e-Bike experience.
Error codes are warnings of potential issues and can be challenging to interpret. In this article, we discuss Tongsheng error codes and how to fix them. Most of the time, they are easy to fix at home. Other times, you need to see an expert.
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Table of Contents
What is Tongsheng?
Tongsheng was founded in 1998 and was among the first to enter the electric bike market. They specialise in electronic components for bikes and offer a range of kits, with the Tongsheng TSDZ2 motor among the most popular. They make good-quality components at a reasonable price point.
Tongsheng is well known for DIY motors, which are not always easy to use, but it does offer motors for bikes on Addmotor, Juiced Bikes, Rad Power Bikes, and many more. Adding a TSDZ2 motor to a bike designed without a motor carries significant risk and excessive heat shrink. A TSDZ2 bike is often a common custom build.
- TSDZ2 250W – The classic torque‑sensor mid‑drive motor (~250 W) for smooth, natural pedal assist on commuter and trekking bikes.
- TSDZ2 350W – Higher‑power version of the TSDZ2 with stronger assist for hillier terrain or heavier riders.
- TSDZ2 500W – Even more torque and power, often used on heavier e‑bikes or bikes needing stronger mid‑drive support (may be restricted depending on local e‑bike laws).
- TSDZ2 Cargo / Heavy‑Duty Variants – Modified TSDZ2 builds tuned for cargo or utility use with enhanced torque delivery and durability.
Complete List of Tongsheng E-Bike Error Codes
E01 Throttle Error
This is usually caused by a throttle that is unplugged, damaged, or stuck. Very rarely, an incorrect voltage throttle signal.
Check that the throttle is correctly on and plugged in. Make sure there’s no damage to any wires. If it persists, you will want to replace the entire throttle unit.
E02 Brake Sensor Error
This is where the brake cutoff sensor is misaligned or not fully returning to its original position.
Check the brake sensor cables and ensure the lever goes fully outward. If it continues to occur, consider replacing the brake sensor.
E03 Speed Sensor Error
The speed sensor is misaligned or damaged, often due to a dirty or faulty sensor or a misaligned magnet on the rear wheel.
Ensure the magnet on the wheel crosses the sensor. Clean the bike to ensure no dirt is getting in the way. If that doesn’t resolve the issue, replace the entire sensor.
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E04 Torque Sensor Error
Commonly caused by a wiring problem or the sensor being out of calibration. Torque sensor errors are widespread on e-Bikes and significantly affect pedal-assist performance.
First, clean the bike of any dirt, and check for ingress around the torque sensor. Recalibrate to ensure it is correctly functioning. If that hasn’t worked, it could be the controller.
E05 Controller Internal Fault
This indicates a fault in the controller, typically caused by water ingress or overheating. This can cause many issues, ranging from a power-down to battery-voltage errors.
A power reset will often resolve this error code, but it's good to check the connections first. Check for damage or water ingress. If you find this, then replace the whole controller.
E06 Over-Temperature
This occurs when the controller or motor is operating at an excessively high temperature. Usually, it is due to improper use of the bike or to excessive power being used for too long.
Let the components cool before starting. It’s good when riding the bike to have a high cadence with less assistance. Ensure you are not at full power for extended periods.
E07 Communication Loss
Communication loss occurs when the bike can’t communicate with other components. Often caused by a loose cable, a faulty display unit, or a motor controller board. The VLCD5 screen is one of theirs.
The solution to fixing the E07 code is to check all the connections and wires. Look for breaks, dirt, and poor connections. If nothing is found, consider a replacement controller. If you see an overcurrent or display-unit error, it could be a faulty controller.
E08 Battery Error
Error E08 occurs when the battery does not produce the correct voltage. It could be from a voltage drop. This is most likely due to a poor connection or a faulty battery.
First, check the connections for dirt or corrosion, then inspect the cables for damage. If they are fine, it’s time to test the battery voltage to determine whether a replacement is needed. An expert can do this for you.
E09 Software Mismatch
E09 often comes up after parts have been changed. This means the firmware on the motor, controller, or battery is different, preventing them from communicating properly.
Updating the firmware is the only way to get around this. Get them all to the most up-to-date, correct firmware. Then reflash (Reset) the controller if required.
When to Visit a Tongsheng Certified Dealer or an E-Bike Mechanic
Working on bikes can sometimes be really easy, and using error codes can help you know where to look and what to look for. Many e-Bike issues can be fixed at home and often don’t require any tools, just a reset or repositioning a sensor.
When it comes to the more technical jobs, it’s good to see a dealer or a mechanic. Opening cases with batteries or electrical components inside isn’t always a good idea for safety reasons, and you could cause more damage in the long run.
It’s good to think through the error code and do what you feel you are capable of, but know when to stop and escalate to the right person to fix it. Another factor to be careful of is using the correct firmware. Most open source firmware is good, but Tongsheng is the best place to get it.
Preventing Tongsheng Electric Bike Error Codes
Error codes do happen, but there are many things you can do to avoid them happening too much. Here’s what we recommend.
- Keep a Clean Bike - A clean bike ensures the sensors perform at their best. It often prevents water and dirt ingress through failed bearing seals. You will see many fewer codes, just keeping dirt and dust away from the bike in storage.
- Regular Checks - Checking your bike regularly will go a long way to avoid error codes. You might find worn cables, which you could protect before they break or even loose connections.
- Stay on top of Firmware Updates - Firmware updates not only improve how the bike works but also help fix bugs and potential communication issues between components. Most companies offer updates through an application.
If you want to learn more, check out our Guide To e-Bike Systems or How Often Does My e-Bike Need Maintenance.
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.
