Bosch eBike Systems
Sensors
503
Speed sensor fault
The drive unit is not receiving a valid signal from the speed sensor on the rear wheel — the most frequently seen Bosch error code in practice. In most cases the spoke magnet has shifted, sits too far from the sensor or the sensor is dirty or its cable damaged. Without a plausible speed signal the system stops assisting.
- Drive system
- Bosch eBike Systems
- Category
- Sensors
- Motor behavior
- assist off
- DIY-friendly?
- possible
Roadside self-help
- Check that the spoke magnet is aligned with the mark on the sensor and only a few millimetres (about 8-14 mm) away
- Clean sensor and magnet and retighten the magnet
- Restart the system
- If the error persists, have sensor and cable checked by a dealer
Possible causes
- Spoke magnet shifted or too far from the sensor high
- Dirty sensor or magnet medium
- Damaged sensor cable medium
- Spoke magnet lost low
Symptoms
- Error 503 on the display, often after wheel removal or transport
- Motor assistance cuts out
- No or implausible speed reading
Inspection / repair
- Difficulty: easy
- DIY: possible
- no dealer tool needed
- Estimated cost: 5–80 €
- Estimated time: 0.1–1 h
- Component: speed sensor
- Component: spoke magnet
- Component: sensor cable
Applies to
Gen2-Gen4 (BES2/BES3)
Displays: Intuvia/Purion/Kiox/Nyon