Shimano STEPS error E905: Incompatible component combination detected
The drive unit has identified one or more paired components (battery, display, or drive unit) that are not on the same compatibility list. When E905 is active, motor assist is cut completely and walk assist is unavailable, so the bike rides like a normal unpowered bicycle. The display will still power up and show the code until the mismatch is resolved.
| Drive system | Shimano STEPS (E5000, E6100, E7000, E8000, EP6, EP801) |
| Severity | Dealer needed |
| Keep riding? | Do not keep riding |
| Typical cost | Expect €0 for a dealer firmware update and compatibility check, rising to roughly €80-€180 for a display swap, €250-€450 for a battery replacement, and €350-€700 if the drive unit itself has to be exchanged. |
Likely causes
- A replacement battery from a different Shimano STEPS generation fitted to the existing drive unit.
- A third-party or aftermarket display installed without checking the compatibility matrix in E-TUBE PROJECT.
- Mixed components across E5000, E6100, E7000, E8000, EP6 and EP801 generations after a partial upgrade.
- A non-genuine battery or drive unit installed by a previous owner or another workshop.
- Corrupted or failed firmware on the drive unit following a botched update, locking out previously matched components.
- Moisture or pin damage in the harness between units causing the handshake to fail.
- Incorrect component selected when ordering a spare using only the visual model number.
How to fix Shimano STEPS error E905
- Stop riding on assist and switch the system off.
- Power down, remove the battery, wait 30 seconds, then refit and power on to rule out a temporary handshake glitch.
- Confirm every unit on the bike (drive unit, battery, display, switch) is a genuine Shimano STEPS part and record the model numbers printed on each label.
- Open E-TUBE PROJECT on a PC or the E-TUBE RIDE app and run a compatibility check using those model numbers.
- Inspect the connectors between the battery, drive unit and display for moisture, bent pins or contamination and clean with contact spray if needed.
- Connect the bike to E-TUBE PROJECT and update firmware on every unit to the latest release, then re-pair the components.
- If the code remains after firmware updates, take the bike to an authorised Shimano dealer so they can identify which unit is outside the compatibility list and quote the correct replacement.
Warranty: Compatibility faults raised by the system are treated as a configuration or component issue rather than a manufacturing defect, so warranty coverage depends on which unit is at fault and proof of genuine purchase; non-genuine parts and water or crash damage are not covered, while a genuine Shimano component failure inside the two-year warranty window is normally replaced free of charge.
Typical cost: Expect €0 for a dealer firmware update and compatibility check, rising to roughly €80-€180 for a display swap, €250-€450 for a battery replacement, and €350-€700 if the drive unit itself has to be exchanged.
Frequently asked
Can I reset Shimano error E905?
No. E905 is a hardware compatibility flag set by the drive unit, not a transient fault, so a power cycle will not clear it. The code disappears only after the mismatched component is replaced or the firmware across all units is updated through E-TUBE PROJECT.
Is it safe to keep riding with E905?
Riding the bike without motor assist is mechanically possible, but on hills or in traffic the loss of power can be hazardous and continuing may trigger further electrical faults. Get the system checked before relying on the bike for any real distance.
What does it cost to fix E905 under warranty?
A firmware update at a dealer is usually free and resolves E905 if caused by outdated software. If a component is genuinely faulty and still within the two-year Shimano warranty, the part is replaced at no charge, but a battery swap on an out-of-warranty system typically runs €250-€450.
Related Shimano STEPS codes
Manuals and video
Official source: si.shimano.com
Not an official Shimano STEPS document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.