Bafang error 25: Torque sensor signal error
Bafang BBS01/BBS02/BBSHD, M-series mid-drives and hub motors (UART & CAN displays)Dealer neededRide with caution
The controller reads no or an implausible torque signal from the bottom bracket sensor. On torque-sensing Bafang systems (M-series, torque BBS variants, hub systems with torque BB) this means assist is weak, jerky or absent; the display shows the code at start-up or when you start pedalling.
Likely causes
- Torque sensor connector loose, wet or corroded
- Sensor cable damaged, often near the bottom bracket
- Pressure on the pedals while switching on (sensor calibrates at power-up)
- Faulty torque sensor or its amplifier board
- Wrong sensor type configured in the controller after a rebuild
How to fix Bafang error 25
- Switch off, take your feet off the pedals, switch on and wait 3 seconds before pedalling
- Check the sensor connector near the bottom bracket; dry, clean and re-seat it
- Inspect the cable for crush damage where it enters the frame
- On systems with a torque calibration option in the display or app, run the calibration
- Have the sensor replaced; on M-series motors the sensor is inside the motor unit
Go to a dealer if: Go to a shop if calibration and a clean connector do not help; the sensor is inside the motor on most systems.
Warranty: If the bike or kit is under warranty (usually 1-2 years via the seller), contact them before opening anything, as opened motors and controllers can void the claim.
Typical cost: External torque BB EUR/USD 60-150; internal sensor on M-series motors EUR/USD 100-300 with labour.
Warranty: If the bike or kit is under warranty (usually 1-2 years via the seller), contact them before opening anything, as opened motors and controllers can void the claim.
Typical cost: External torque BB EUR/USD 60-150; internal sensor on M-series motors EUR/USD 100-300 with labour.
Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.
Frequently asked
Can I reset error 25?
Power cycle with no load on the pedals. If the sensor is faulty, the code returns when you pedal.
Can I keep riding with error 25?
Usually you can ride with reduced or no assist. Throttle may still work if fitted.
Warranty?
Yes, torque sensor failure is a standard warranty case unless the cable was crushed.
Related Bafang codes
Not an official Bafang document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.