Knowledge base
Speed signal
Possible causes
- Spoke magnet moved/missing
- Speed sensor gap/cable
- Wheel size setting
Safe test steps
- Does the magnet pass the sensor, gap (manufacturer value, often a few mm).
- Cable damage along the chainstay.
Workshop reference values
- No general documented measurement value – manufacturer service documentation required.
Repair approach
- Align magnet/sensor, repair cable; set wheel size correctly.
Tools needed
- Basic hand tools, insulated screwdrivers
- Digital multimeter (CAT III, fused inputs)
Safety
- Tampering with the speed signal may be illegal and can lock the system.
Related verified fault codes
| Code | Meaning | Component | Reliability |
|---|---|---|---|
| Bosch 503 | Speed sensor fault | Speed signal | Per manufacturer documentation |
| Bosch 504 | Speed signal manipulation detected | Speed signal | Per manufacturer documentation |
| Shimano STEPS W011 | Travel speed cannot be detected | Speed signal | Per manufacturer documentation |
| Shimano STEPS E014 | Speed sensor may be installed in the wrong position | Speed signal | Per manufacturer documentation |
| Bafang 21 | Speed sensor fault | Speed signal | Per manufacturer documentation |
| KT (Kunteng) 05 | Axle speed sensor abnormality (torque-sensor systems only) – KT-LCD3 manual | Speed signal | Widely published – may differ by model/firmware |