Bosch error 0x503001: Speed sensor signal missing or invalid
The drive system has lost or cannot read a valid signal from the rear-wheel speed sensor. Motor support is restricted and the speed readout drops to 0 km/h, so assistance, walk mode, and accurate trip data no longer work. The bike still rolls and brakes normally, but it behaves like an unpowered bicycle until the fault is cleared.
| Drive system | Bosch eBike (DiagnosticTool / eBike Flow hex code) |
| Severity | Dealer needed |
| Keep riding? | Ride with caution |
| Typical cost | Sensor replacement typically runs EUR 30-80 for the part plus EUR 40-90 for dealer labour, while harness or drive-unit-related repairs can push the total to EUR 150-300. |
Likely causes
- Magnet missing from the rear-wheel spoke or knocked out of alignment during transport or wheel removal
- Magnet-to-sensor gap outside the 5-17 mm working window, often after a wheel refit
- Loose, corroded, or unplugged sensor connector at the dropout or drive unit
- Damaged sensor cable chafed against the chainstay or frame
- Cracked or contaminated sensor head from impact, grit, or metal swarf
- Internal sensor failure or a drive-unit wiring fault upstream of the sensor
How to fix Bosch error 0x503001
- Inspect the magnet on the rear-wheel spoke: confirm it is present, the correct side faces the sensor, and it is firmly seated in its holder.
- Measure the gap between the magnet and the sensor body with feeler gauges; adjust the magnet position or the sensor mounting until the distance sits between 5 and 17 mm.
- Clean the sensor face and the magnet of any oil, debris, or ferrous contamination, then verify the wheel passes the sensor cleanly through one full rotation.
- Check the sensor connector at the dropout and at the drive unit for full engagement, corrosion, or bent pins; reseat firmly.
- Using a multimeter at the sensor connector, measure supply voltage from the drive unit; it should read around 3.3 V with at least 3.1 V under load.
- If wiring and voltage are correct but the error persists, the sensor itself is suspect and needs replacement.
- Take the bike to an authorised Bosch dealer for a DiagnosticTool read-through, harness check, and component replacement if the previous steps do not resolve the fault.
Warranty: A genuine sensor or wiring fault inside the two-year component warranty is normally covered by Bosch; crash damage, water ingress, lost magnets, and DIY wiring faults are not.
Typical cost: Sensor replacement typically runs EUR 30-80 for the part plus EUR 40-90 for dealer labour, while harness or drive-unit-related repairs can push the total to EUR 150-300.
Frequently asked
Can I reset bosch error 0x503001?
No. This code does not clear on its own and cannot be wiped with the display power cycle. The speed-sensor fault has to be fixed mechanically or electrically first, then the dealer clears the code with DiagnosticTool.
Is it safe to keep riding with 0x503001?
The bike remains rideable without power, so short trips home are acceptable. Avoid any route that depends on motor support, climb assistance, or accurate speed and distance readings until the fault is resolved.
How much will the repair cost and is it under warranty?
Out of warranty, expect roughly EUR 70-170 at a dealer for diagnosis, sensor, and labour. Within two years and with no crash or water damage, a genuine Bosch sensor fault is usually covered at no cost.
Related Bosch codes
Manuals and video
- Bosch eBike Help Center: official error-code index
- Bosch eBike downloads: quick start guides and battery guide
- Bosch eBike dealer search (DiagnosticTool readout)
Official source: www.ridewill.com
Not an official Bosch document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.