Battery & Mounting
Check the charge and the connection. A poorly secured battery may disconnect due to vibrations.
Solution: Remove and reinsert the battery until you hear a clear "click."
Why does my e-bike suddenly stop working?
An electric bike is a complex set of electronic components. If just one link in the chain malfunctions, the entire system can shut down. In this article, we take an in-depth look at the possible causes of your e-bike suddenly stopping and offer detailed solutions to get you back in the saddle. See also our other article on the most common problems.
Written by: Hanna Stevens | January 8, 2025 | Reading time: 6 minutes
More about the author: Hanna Stevens
Hanna is an avid cyclist who loves exploring new routes and sharing her experiences to inspire others to get on their bikes more often.
Key findings
- Always start with the battery and the contact points: this solves the problem surprisingly often.
- A displaced radius magnet or dirty sensor can completely cut off assistance.
- If the problem recurs regularly or if you smell something burning: stop immediately and consult a specialist.
The battery: the prime suspect
The battery is the heart of your electric bike. When the motor stops, it's the first thing to check.
Charge level and capacity
It may seem obvious, but start by checking that the battery is actually charged. Sometimes the charger is not properly connected. In addition, many e-bikes have a protection mechanism: when the battery capacity drops below about 10 to 20%, the system automatically cuts off assistance to prevent deep discharge. The display may still light up, but you will no longer feel the motor assistance.
Connection and fastening
A very common problem, especially on bikes with batteries mounted on the luggage rack or integrated into the frame, is a poorly secured battery. If it is not properly locked in place (with a "click"), vibrations caused by riding, for example over speed bumps or cobblestones, can cause a momentary power cut.
Solution: Remove the battery and reinsert it. Make sure you hear a distinct click and that it does not move in its holder. On some models, particularly Gazelle models, temporarily adding a little foam to fill the gap can serve as a temporary solution.
Corrosion and dirt
The contacts between the battery and the bike can become dirty or oxidized due to humidity and cold weather, which disrupts energy transfer.
Solution: Inspect the contact points. Are they dirty? Clean them gently with a dry cloth. You can also use a professional contact spray, making sure everything is completely dry before replacing the battery.
Sensors: the bike's nervous system
Your e-bike uses smart sensors to determine the level of assistance required. If these sensors send incorrect information—or no information at all—the motor will stop.
The speed sensor and magnet
Most e-bikes are equipped with a speed sensor on the rear wheel, connected to a small magnet attached to a spoke. If this magnet moves (for example, after an impact), the sensor no longer detects the wheel's rotation. As a result, the motor "thinks" that you are stationary and cuts off the assistance, often accompanied by an error code (such as 503 for Bosch or W011 for Shimano).
Solution: Check the magnet on the spoke. It must pass at a specific distance from the sensor (often between 3 and 17 mm). Realign the magnet so that it passes exactly in front of the sensor.
Torque sensor and rotation sensor
The bottom bracket usually has sensors that measure whether you are pedaling (rotation sensor) and how hard you are pedaling (torque sensor). If they are covered in mud or grease, they may malfunction.
Solution: Clean the area around the crankset with soapy water. On more advanced systems, such as Shimano, the torque sensor can become misaligned if you press down on the pedals when turning on the bike. This causes error codes such as W013. The solution is simple: turn off the bike, remove your feet from the pedals, then turn it back on.
Brake sensors
Some e-bikes have sensors in the brake levers that immediately cut the motor when you brake. If a lever does not return correctly or if the sensor remains blocked, the bike "thinks" that you are braking continuously and the assistance does not activate.
The screen and controller
The controller is the brain of the bike: it manages communication between the battery, motor, and display.
Screen contact issues
Removable screens are susceptible to connection problems. If the copper contacts on the back become oxidized due to rain or condensation, the screen may turn off or display incorrect information, cutting off assistance.
Solution: Remove the screen and clean the contacts with a dry cloth. Also check that the screen is properly engaged in its holder.
Software and error codes
Sometimes the hardware is in good condition but the software is outdated or unstable. Many modern systems (such as Bosch or Shimano) display specific error codes that aid in diagnosis. Outdated software can also lead to decreased performance.
Solution: Try resetting the system by turning the bike off and then on again. If this does not work, consult the manual for the relevant error code or visit a dealer for a software update.
Wiring and connectors
Electric bikes contain many cables that carry power and signals. Vibrations while riding can loosen some connectors, especially near the motor, handlebars, or controller.
Solution: Follow the visible cables. Do you see a break or a loose connection? Firmly push in any loose connectors. If the wiring runs inside the frame, checking it becomes more complex and the intervention of a specialist is often necessary.
The engine itself
Although modern e-bike motors are robust, internal mechanical or electrical problems can occur.
Overheating
In the event of heavy use, for example when climbing a steep hill with a high gear ratio and maximum assistance, the motor may overheat. The system will then activate its safety feature and switch off.
Solution: Touch the motor casing. Is it very hot? Turn off the bike and let the motor cool down for at least 10 minutes in the shade.
Internal damage
Did you hear any unusual noises (squeaking, clunking) before the engine stopped? This could indicate damaged gears or bearings. This type of problem cannot be repaired by yourself: it needs to be serviced or replaced by a professional.
Specific issues by brand
Each brand has its own specific characteristics. See our detailed article on error codes by brand.
| Brand | Common problem | Example / error code |
|---|---|---|
| Shimano | Pressure on the pedals when starting | W013, W103, E012 |
| Bosch | Displaced radius magnet | 503 |
| Gazelle (Innergy) | Corrosion of screen contacts | Display issues |
| Stella | Vibrating battery | Engine shutdown + lighting |
| Qwic | Engine overheating | Error code 80 |
When should you call in a professional?
If you have checked the battery, cleaned the sensors, reconnected the cables, and reset the system, but the bike still does not work, it is time to consult an expert. Especially if the bike is still under warranty (usually 2 years), avoid any work on the motor or controller, as this may void the warranty.
- There is visible damage to the engine or battery (cracks, dents).
- If you smell something burning or see smoke (stop immediately!).
- The screen displays error codes that are not listed in the manual.
- You don't feel comfortable working on electrical components.
Prevention: prevention is better than cure
To avoid breaking down again, regular maintenance is essential:
- Cleanliness: Clean your bike regularly, but never use a pressure washer directly on the motor or battery.
- Battery maintenance: store it at room temperature and recharge it at least once every three months if the bike is not in use.
- Inspection: Check a few times a year that all screws are tight and that tires pressure tires correct; tires put unnecessary strain on the battery.
Conclusion
Diagnosis: Electric Bike Breakdown
Why does my e-bike suddenly stop?
Magnets & Sensors
A displaced radius magnet (error 503) prevents the motor from detecting your speed.
Tip: Align the magnet facing the sensor (distance of 3 to 17 mm).
Screen & Contacts
Moisture or oxidation at the contact points can cut off the electrical assistance.
Solution: Clean the contacts with a dry, clean cloth.
Engine Overheating
A steep incline or prolonged effort can cause the engine to overheat and activate its safety features.
Tip: Turn off the bike and let it cool down for 10 minutes in the shade.
Error Codes
The system may malfunction (e.g., W013 on Shimano if you pedal when starting).
Solution: Restart without stepping on the pedals.
Sustainable Maintenance
High-pressure water is the number one enemy of electronic components.
Golden rule: Clean with soapy water, never with a high-pressure jet.
When an e-bike stops working, it often seems serious, but in practice, it is frequently a minor issue. Think of your bike's system as an orchestra: the battery is the conductor, the sensors are the score, and the motor is the musician. If the conductor loses the beat (battery not properly secured) or the score is out of tune (sensor displaced), the music stops, even if the musician is excellent. By methodically checking the basics, from the battery to the magnet, you can often get the orchestra back on track yourself.
FAQ
Why is my e-bike's display working but the assistance isn't?
The battery may be below the safety threshold (approximately 10–20%) or there may be a sensor or contact issue. Check the position of the battery, the contacts, and the spoke magnet.
What does error code 503 mean at Bosch?
This usually indicates a problem with the speed sensor, often a displaced spoke magnet. Realign the magnet and sensor.
Why should you not press the pedals when starting (Shimano)?
Because the torque sensor may become misaligned and generate error codes such as W013. Turn off the bike, remove your feet from the pedals, and turn it back on.
Can rain cause my e-bike to break down?
Yes, particularly due to oxidation or condensation on the battery contacts or removable screen. Drying and cleaning the contacts often helps.
What should I do if my engine overheats and shuts down?
Allow the motor to cool for at least 10 minutes in the shade. Overheating usually occurs during heavy use with high assistance.