Bafang error 09: Motor phase error
Bafang BBS01/BBS02/BBSHD, M-series mid-drives and hub motors (UART & CAN displays)Dealer neededDo not keep riding
The controller detected a fault on one of the three motor phase wires: open circuit, short, or an unbalanced current. Symptoms are a motor that clicks, cogs, vibrates or does nothing, sometimes with a burnt smell. Treat it as serious.
Likely causes
- Broken or corroded phase wire in the motor connector
- Motor cable cut or crushed near the axle or dropout
- Burnt motor windings after overheating or water ingress
- Failed MOSFET in the controller
- Motor connector not pushed fully home after wheel removal
How to fix Bafang error 09
- Unplug and inspect the motor connector for burnt, discoloured or corroded phase pins; clean and re-seat
- Check the phase wires for continuity and for shorts to each other or to the axle (multimeter)
- Spin the wheel by hand with the motor unplugged: strong cogging or a scraping noise points to the motor
- Smell the controller and motor; a burnt smell means replacement rather than repair
- Have a shop test the controller on a known-good motor, or swap the controller if you have a spare
Go to a dealer if: Go to a shop as soon as the connector looks fine; phase faults usually mean motor or controller replacement and a wrong guess is expensive.
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: Motor cable EUR/USD 30-60; controller EUR/USD 80-250; a burnt hub motor or mid-drive stator EUR/USD 200-500.
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: Motor cable EUR/USD 30-60; controller EUR/USD 80-250; a burnt hub motor or mid-drive stator EUR/USD 200-500.
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 09?
Power cycling will not fix a phase fault. Only a loose connector clears on its own.
Can I keep riding with error 09?
No. A phase short can destroy the controller within minutes. Pedal without assist.
Warranty?
Motor windings and controllers are core warranty parts; water damage and crash damage are typical exclusions.
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.