Shimano STEPS · Battery
E021 Shimano STEPS error code E021
Connected battery conforms to the standard but is not supported
Per manufacturer documentation
Note
Meaning may depend on model, display and firmware – verify with the manual of the exact type.
Possible causes
General, component-based causes – not a manufacturer-specific statement.
- Aged cells, increased internal resistance
- Weak or discharged cell group
- Contact fault at battery connector/mount
- BMS protection or BMS fault
Safe test steps
- Resting voltage at the pack output vs. the nominal class (S × 3.6 V nominal, S × 4.20 V full for Li-ion).
- Load test with current: R = ΔU / I (E-Bike Doctor battery calculator).
- Condition of mount contacts, discoloration, play.
Workshop reference values
- Li-ion cell: 3.6–3.7 V nominal, 4.20 V full; manufacturer minimum typically 2.5–3.0 V (per datasheet).
- Pack full voltage (Li-ion): 7S 29.4 V · 10S 42.0 V · 13S 54.6 V · 14S 58.8 V.
Repair approach
- Full charge with the original charger, then re-measure.
- Pack repair/re-celling only by a qualified battery shop with identical matched cells; otherwise replace the pack.
Tools needed
- Digital multimeter (CAT III, fused inputs)
- Fused load tester or clamp meter
- Manufacturer dealer diagnostic tool/software (if available)
Safety
- Do not charge or open a swollen, hot, damaged, hissing or smelling pack – isolate it safely.
- Never connect an ammeter directly across the battery. Never bypass the BMS.
This information does not replace manufacturer service documentation. Work on batteries and high-voltage parts only with the appropriate expertise.
Related fault codes
E022Connected battery does not conform to system standardsW010Drive unit temperature is higher than normalW011Travel speed cannot be detectedW013Torque sensor initialisation was not completed normallyW032Electronic derailleur may have been replaced with a mechanical oneE010System error detectedE013Abnormality in drive unit firmwareE014Speed sensor may be installed in the wrong position