Shimano STEPS Error Code E031 (Chain Tension / Crank Position): Meaning + Next Steps
TL;DR
E031 = Chain tension may not be adjusted or the crank may not be installed properly; assist may not work (shifting may still work).
Official next step: Consult an agency/dealer.
Quick fix (safe DIY first)
- If your bike uses a chain drive with adjustable tension, do a basic visual check for extremely tight/loose tension.
- Check for obvious crank looseness or unusual play.
- Because Shimano’s remedy is dealer-side, treat this as a service code if it persists.
60-second checks (the things that cause repeat codes)
- Any recent crank removal, bottom bracket work, or chain tension adjustment?
- Does pedaling feel unusually stiff or ‘notchy’?
What usually causes E031
- Loose or intermittent connectors (battery mount, motor harness, display/switch).
- Water/corrosion at contacts after rain/washing.
- Firmware/compatibility mismatch after service or a component swap.
- In some cases, an internal sensor or control-unit fault that needs dealer diagnostics.
When to stop DIY (go to a Shimano STEPS dealer)
Go to a dealer if:
– The code returns immediately after a clean restart.
– Assistance cuts in/out while riding (safety issue).
– You see damaged wiring, bent pins, corrosion, or water intrusion.
– The official remedy for the code is “consult an agency/dealer.”
Don’t do this
- Don’t ride hard with a suspected crank/BB issue—mechanical damage can follow.
Related guides (closed-loop)
- Shimano STEPS error codes index: https://jieli-electric.com/shimano-steps-error-codes/
- E-bike error codes hub: https://jieli-electric.com/e-bike-error-codes/
- Speed & power thresholds: https://jieli-electric.com/speed-power-thresholds/
- Laws & Safety Hub: https://jieli-electric.com/laws-safety/