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Shimano STEPS error codes

Shimano error E025
Battery doesn't recognize the drive unit

The battery can't identify the motor it's connected to.

Checked against Shimano's own manual: October 23, 2026.

A short list, on purpose. These are the Shimano codes we could confirm in Shimano's own manuals. Most come from Shimano's Japanese manual for the E8080 system and are translated, so follow each source link for Shimano's exact wording. For any code not listed, use Shimano's official lookup at si.shimano.com/error.
Battery hot, swollen, leaking or smells strange? Stop and read battery safety first. If there's smoke, get away and call 911.

What Shimano says

The battery doesn't recognize the drive unit. (Shown as one flash of the battery's light.)

Shimano's recommended steps

  1. Use a genuine Shimano battery.
  2. Check the power cable.
  3. Contact your distributor or dealer.

Summarized from Shimano STEPS battery user manual (error E025), checked October 23, 2026. Follow the link for Shimano's exact wording.

If it keeps coming back

If the code comes back after one restart, stop using the assist and have the bike checked by a mechanic who works on Shimano systems. Bikes Plus has diagnostic tools for Shimano and most other major motor systems.

Write down the code and what you were doing when it appeared. That saves time at the shop.

Make sure it's a Shimano code

Error numbers mean different things on different systems. This page covers Shimano STEPS and EP e-bike systems. Codes starting with W are warnings, which clear when conditions improve; codes starting with E are errors, which point to a possible fault. Shimano's E-TUBE PROJECT Cyclist app can read the code from the bike.