Shimano STEPS error E025: Drive unit not recognised by battery
The battery cannot identify the drive unit as a genuine Shimano component, or the power cord linking the two has lost contact. When this fault is active the motor cuts assist, walk assist stops working, and the bike behaves like a normal unpowered bicycle. The display stays on so the code remains visible for diagnosis.
| 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 connector reseat under warranty, €40-€120 for a replacement power cable, or €600-€1,200 for a drive unit replacement if the unit is non-genuine or out of warranty. |
Likely causes
- Power cable between battery and drive unit disconnected or loose at one end
- Corroded, bent, or contaminated pins in the power connector
- Aftermarket or non-genuine drive unit fitted to the bike
- Damaged cable from a routing pinch, frame strike, or crash impact
- Battery firmware mismatch with drive unit following a software update
- Water or dirt ingress in the connector causing intermittent contact
How to fix Shimano STEPS error E025
- Switch off the system and remove the battery from its mount.
- Inspect the power cable connector at both the battery and drive unit ends for bent pins, moisture, or debris.
- Clean the contacts with isopropyl alcohol and a lint-free cloth, then let them dry fully.
- Re-seat the battery firmly and confirm the power connector is fully engaged and latched.
- Power on the system and check whether E025 clears from the display.
- If the code returns, do not fit a non-genuine drive unit; only genuine units are accepted by the battery.
- Take the bike to an authorised Shimano dealer for cable continuity checks and drive unit identification with the Shimano diagnostic tool.
Warranty: A genuine component or wiring fault inside the two-year warranty period is normally covered, while water ingress, crash damage, and non-genuine replacements are excluded.
Typical cost: Expect €0 for a connector reseat under warranty, €40-€120 for a replacement power cable, or €600-€1,200 for a drive unit replacement if the unit is non-genuine or out of warranty.
Frequently asked
Can I reset Shimano error E025?
A power cycle can clear E025 if the cause was a temporary contact loss at the power connector. If the code returns after re-seating the battery and inspecting the cable, the system cannot be reset by the rider and needs dealer diagnostics.
Is it safe to keep riding with E025?
No, motor assist and walk assist are both disabled, so the bike rides unpowered and continued use can worsen an underlying wiring fault. Move the bike home or to a workshop by pedalling only, not under throttle or assist.
Will warranty cover E025 and what will it cost?
A genuine drive unit or cable fault within two years is normally replaced at no cost. Outside warranty, expect €40-€120 for a power cable and €600-€1,200 for a drive unit if a non-genuine unit was fitted.
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.