Yamaha engine error codes and how to resolve them
When an electric bike equipped with a Yamaha motor displays an error code, it can cause uncertainty and even frustration. However, these codes are designed to help: they indicate precisely which component requires attention. In many cases, the causes are relatively simple, such as dirty sensors, poor battery contact, or a poorly connected cable. In this article, we clearly outline the most common Yamaha motor errors, explain what they mean, and suggest solutions you can try yourself.
Written by: Hanna Stevens | December 12, 2025 | Reading time: 7 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
- Many Yamaha error codes have a simple cause, such as dirt, poor contacts, or temporary communication problems.
- Restarting and cleaning can resolve most malfunctions, particularly those related to sensors and the battery.
- Persistent or internal engine errors require professional diagnosis; attempting to fix them yourself poses risks to safety and voids the warranty.
1. Sensors (speed, torque, and crank)
Error code 1 (or E01): Speed sensor
Cause: The system is not receiving a correct signal regarding your speed. This is often due to a dirty magnet on the spoke or one that is misaligned with the sensor on the frame, or a loose cable.
Solution: Check that the magnet and sensor are clean. Ensure that the distance between the magnet and sensor is approximately 5 to 17 mm and that they are correctly aligned. Also check the cable for any damage.
Error code 2 (or E02) and codes 31 to 37: Torque sensor
Cause: This sensor measures the force exerted on the pedals. A malfunction results in irregular or non-existent assistance. The causes are often calibration errors or wiring problems. Code 31 specifically indicates the absence of a communication signal.
Solution: Turn the electric bike off and then on again (restart). If this does not work, a visit to a specialist is usually necessary, as replacement requires special tools.
Error code 3 (or E03) and codes 38/39: Pedal or crank sensor
Cause: Anomaly in the detection of pedal rotation, often due to dirt or blockages around the bottom bracket.
Solution: Carefully clean the area around the pedals and bottom bracket. Check the cables. If the problem persists, the sensor may be defective.
2. Battery and power supply
Error code 4 (or E04): Battery problem
Cause: Common code indicating a dead battery or poor contact between the battery and the engine.
Solution: Ensure the battery is fully charged. Remove it, clean the contacts, and reinsert it correctly.
Error code 71: Battery communication error
Cause: The motor is not receiving any data from the battery. This often occurs when the battery is not properly secured (vibration) or when the contacts are dirty or oxidized.
Solution: Remove the battery and clean the contacts (for example, with contact cleaner spray). Replace the battery and make sure it is securely locked in place, with no play. Sometimes, simply shutting down and restarting the system is enough.
Error code 9 (or E09) and codes 33/34: Voltage problems
Cause: Incorrect voltage, possibly due to a faulty charger or wiring problems.
Solution: Check the charger and try restarting the system.
3. Temperature and overheating
Error code 5 (or E05) and codes 64/65: Temperature sensor
Cause: The system is too hot (e.g., during a steep climb or in intense sunlight) or, conversely, extremely cold (-20°C).
Solution: Allow the bike to cool down in the shade or warm up. Adjust your riding style by using lighter gears on inclines to reduce the load on the motor.
4. Display and communication
Error codes 12 and 13: Communication with the display
Cause: Communication with the display is interrupted, often due to a damaged cable or a faulty display.
Solution: Check the display cables and connectors. In severe cases, the display or cable must be replaced.
Error code 8 (or E08): Display problem
Cause: Malfunction of the display itself or the connection cable.
Solution: Check the cable connection between the display and the motor.
5. Internal engine errors
Codes 61, 62, 63, 67
Cause: Serious technical errors such as overcurrent in the motor phases, internal data reading errors, or loose internal wiring.
Solution: Restarting is usually not sufficient; the controller or motor must be replaced by an authorized dealer.
Yamaha E-Bike Error Code Summary Table
| Error code | Component / Description | Possible cause | Solution |
|---|---|---|---|
| 1 / E01 | Speed sensor | Magnet dirty, misplaced, or sensor disconnected | Clean magnet/sensor, align (0.2–0.7 in), check cable |
| 2 / E02 | Torque sensor | Problem measuring pedaling force | Turn off/turn back on (without pressing the pedals), otherwise contact your dealer. |
| 3 / E03 | Crank/pedal sensor | Sensor dirty, blocked, or defective | Clean the bottom bracket shell, check the cables |
| 4 / E04 | Battery (empty/contact) | Battery almost empty or poor contact | Recharge, clean the contacts, and reinsert the battery properly. |
| 5 / E05 | Temperature | Overheating or extreme cold | Allow to cool/heat, adjust driving style |
| 8 / E08 | Display | Display or cable problem | Check the cable |
| 9 / E09 | Voltage | Incorrect voltage | Check charger and cables, restart |
| 12 | Display communication | Communication interrupted | Check connectors, replace if necessary |
| 13 | Display data error | No data received | Replace the display or check compatibility |
| 31 | Torque sensor | No communication signal | Restart, otherwise replacement (retailer) |
| 33–37 | Voltage (sensors) | Abnormal voltage | Restarting, often necessary replacement |
| 38 / 39 | Crank sensor | Fault or short circuit | Replacement by a dealer |
| 61 | Controller (phase U) | Overcurrent or abnormal voltage | Restart, or replace |
| 62 | Motor (overcurrent) | Overcurrent detected | Serious error, replacement required |
| 63 | Controller data error | Reading error | Restart, or replace |
| 64 | PCB temperature | Card too cold or too hot | Let it acclimatize, restart |
| 67 | Motor wiring | Loose internal wires | Repair or replace |
| 71 | Battery communication | No battery data | Clean contacts, secure battery |
| 73 | Battery voltage | Voltage too high | Replace controller or battery |
| 79 | DC-DC converter | Abnormal current | Restart, or replace |
Basic steps applicable to many error codes
- Restart: Many temporary errors (codes 7, 31, 33, 61, etc.) can be resolved by turning the system off and then back on again.
- Cleaning: Keep the sensors (especially the speed sensor) and battery contacts clean.
- Wiring: Regularly check that the cables are securely fastened and undamaged.
- Dealer: If a code persists or cannot be resolved by restarting or cleaning, contact an authorized Yamaha service center. Any work on internal electrical components may void the warranty.
FAQ
Can I continue driving with an error code?
It depends on the code. For some codes, assistance is reduced or non-existent, but it is possible to continue driving without assistance. In the event of serious engine or controller errors (codes 61, 62, or 67), it is not recommended to continue driving.
Is restarting always sufficient?
Restarting the device may resolve temporary issues, such as communication or voltage problems. If the code reappears, it is usually a structural problem requiring further diagnosis.
Can I replace parts on a Yamaha electric bike myself?
Simple operations, such as cleaning sensors or battery contacts, are safe. Replacing internal electrical components or sensors often requires specialized tools and may void the warranty.
Why are battery-related codes so common?
Batteries are sensitive to dirt, vibrations, and contact issues. Poor contact or oxidized terminals are common causes of E04 or 71 codes.
When should I go to a dealer immediately?
If a code persists after restarting and cleaning, or if it is an internal engine or controller error, a visit to an authorized Yamaha service center is essential.