If you ride a bike with a Yamaha drive system and your display shows an error code, this page helps you:
- understand what the code means,
- run the safe DIY checks first,
- and know when it’s time to stop and see a dealer.
This hub currently contains 39 code pages for Yamaha.
Start here: the 60‑second “don’t make it worse” checklist
- Stop safely and take a photo of the code (and any blinking patterns).
- Power off fully (wait ~10–20 seconds). If needed, remove the battery briefly.
- Check the obvious connectors you can reach without disassembly (battery seat, display mount, visible harness plugs).
- If the bike cuts power unpredictably, smells hot, or shows battery/over‑current faults: stop riding and get it inspected.
Choose your path (quick decision tool)
| What you’re seeing | Do this first | When to stop DIY |
|---|---|---|
| Code shows after rain / washing | Dry contacts, reseat connectors, restart | Corrosion, bent pins, repeat code |
| Code shows only on bumps | Suspect loose battery/connector fit | Repeat cutouts in traffic |
| Code appears right after charging | Let battery rest, restart, re-check | Battery voltage / internal faults repeat |
| Code appears during hard climbs | Lower assist, increase cadence, cool down | Overheat/overcurrent keeps returning |
| Code returns immediately on restart | Go straight to the code page below | Dealer-level diagnostics likely |
Good “first pages” to check
Start with the closest match, then follow the related links at the bottom of each page (that’s the closed‑loop).
- Error 12 — Stopped communications to the display unit (What It Means + Fix
- Error 13 — Communication data failure to the display unit (What It Means + Fix
- Error 15 — Display comes off from the holder (What It Means + Fix
- Error 16 — Encoder disconnected or red wire is short-circuited (What It Means + Fix
- Error 17 — Encoder black wire is short-circuited (What It Means + Fix
- Error 20 — Torque sensor disconnected (What It Means + Fix
Browse all Yamaha codes by topic
Torque / crank sensing
- Error 20 — Torque sensor disconnected (What It Means + Fix
- Error 21 — Torque sensor short-circuited (What It Means + Fix
- Error 22 — Wiring failure between the torque sensor and the controller (What It Means…
- Error 23 — Torque sensor abnormal voltage (slight voltage rise) detected during runnin…
- Error 24 — Torque sensor abnormal voltage (high constant voltage) detected during runn…
- Error 25 — Torque sensor abnormal voltage (other) detected during running (What It Mea…
- Error 26 — Torque sensor abnormal voltage at low speeds (detected during running) (Wha…
- Error 27 — Wiring failure between torque-sensor coil and circuit board (wire chatterin…
- Error 28 — Wiring failure between torque-sensor coil and circuit board (wire chatterin…
- Error 29 — Torque sensor abnormal no-load voltage (What It Means + Fix
- Error 30 — Torque sensor abnormal voltage (high constant voltage) detected during runn…
- Error 31 — Torque sensor abnormal voltage (slight voltage rise) detected during runnin…
- Error 32 — Torque sensor or crank sensor failure (What It Means + Fix
- Error 33 — Crank sensor short-circuited or crank sensor failure (What It Means + Fix
Motor phases, current & rotation
- Error 40 — Motor: 3 lead wires are disconnected (What It Means + Fix
- Error 41 — Motor: yellow lead wire disconnected (U phase) (What It Means + Fix
- Error 42 — Motor: blue lead wire disconnected (V phase) (What It Means + Fix
- Error 43 — Motor: white lead wire disconnected (W phase) (What It Means + Fix
- Error 50 — Controller: abnormal voltage of U-phase current sensor while motor is not o…
- Error 51 — Controller: abnormal voltage of V-phase current sensor while motor is not o…
- Error 52 — Controller: abnormal voltage of W-phase current sensor while motor is not o…
- Error 53 — Motor: overcurrent applied to U phase (What It Means + Fix
- Error 54 — Motor: overcurrent applied to V phase (What It Means + Fix
- Error 55 — Motor: overcurrent applied to W phase (What It Means + Fix
- Error 56 — Abnormal DC current (What It Means + Fix
Temperature & board sensors
- Error 80 — Controller: circuit board temperature too low (−20°C) (What It Means + Fix
- Error 81 — Controller: circuit board temperature too high (125°C, including DC circuit…
- Error 82 — Controller: sensor on the board is nearly detached (What It Means + Fix
- Error 89 — Controller: circuit board temperature too high (90°C) — assist normal but c…
Controller power & memory
- Error 60 — Controller: not within the 12V output range (What It Means + Fix
- Error 70 — Controller: external memory data error (What It Means + Fix
- Error 71 — Controller: failure in data reading (What It Means + Fix
Common mistakes that waste time (and cause repeat codes)
| Mistake | What it causes | Better move |
|---|---|---|
| Turning the bike on while pushing hard on the pedals | Sensor init errors / instant re-trigger | Power on with no load on pedals |
| Pressure-washing the motor/battery/display area | Water in connectors → comm faults | Gentle rinse, then dry + protect contacts |
| Ignoring “only happens on bumps” | Intermittent power loss (unsafe) | Check battery latch/seat + harness strain |
| Chasing firmware without basics | Repeat faults + partial updates | Do connectors first, then update all units |
| Riding through battery/overcurrent faults | Heat + damage risk | Stop riding; get battery/controller checked |
Related site tools (keep the hub loop)
- All brands: https://jieli-electric.com/e-bike-error-codes/
- E‑bike class decision tool: https://jieli-electric.com/e-bike-class-decision-tool/
- Mods & DIY legal checklist: https://jieli-electric.com/e-bike-mods-diy-kits-legal-checklist/
- Speed & power thresholds: https://jieli-electric.com/speed-power-thresholds/
- Laws & Safety hub: https://jieli-electric.com/laws-safety/
Official resources (for this brand)
- Yamaha eBike Systems (support pages vary by region): https://www.yamaha.com/