Error code library

30 codes across 4 controller families. Type a code, a symptom or a brand — the list filters as you go.

A code tells you what the controller cannot talk to, not what is broken. If yours is not listed, or clears and comes back, the first-checks guide covers what usually causes it.

GENERIC / KT CONTROLLER

Most off-brand & white-label e-bikes

Code	Meaning	First check
E02	Brake cutoff / lever stuck	Squeeze & release each lever — confirm it springs back freely
E06	Low voltage	Charge battery; verify with multimeter if charging doesn't clear it
E07	Motor Hall sensor fault	Check Hall sensor wire at axle for damage or moisture
E08	Motor phase wire fault	Inspect the three thick motor phase wires for cuts or bad connectors
E09	Controller internal fault	Reseat all connectors; persistent = likely controller replacement
E10–12	Brake sensor error	Check brake sensor connectors and magnet alignment at each lever
E21	Speed sensor fault	Check spoke magnet; sensor gap should be 2–3 mm
E30	Display–controller comm failure	Check display cable at both ends; try a known-good cable

BAFANG

OEM e-bikes & conversion kits — very widely used

Code	Meaning	First check
04	Throttle not at zero on startup	Release throttle fully before power-on; test return spring
05	Throttle Hall sensor abnormality	Measure throttle output voltage — should be 0.8–4.2 V range
06	Low voltage protection	Charge battery; check BMS for cell imbalance
07	Overvoltage protection	Test charger output — faulty charger can overcharge the pack
08	Hall sensor open circuit	Inspect Hall sensor harness at axle for corrosion or pinch
09	Phase wire short / open circuit	Check three motor phase wires; test continuity on each
10	Controller overheating	Allow to cool; check for over-current conditions
21	Speed sensor abnormality	Reposition spoke magnet; confirm sensor gap
22	BMS communication fault	Reseat battery; check comm port for debris
30	Controller–display comm failure	Replace display cable first — far cheaper than the controller

BOSCH

Premium & performance e-bikes

Code	Meaning	First check
503	Speed sensor problem	Check spoke magnet; align with frame sensor within 3 mm
414	Component comm error	Check all cables: motor, display, battery
424	Drive unit comm error	Reseat motor connector; inspect for moisture at housing
430	Display comm error	Check display cable at both ends; try known-good display
510	Sensor calibration error	Power cycle; persistent = Bosch diagnostic tool required
540	Motor temp too high	Allow to cool; investigate if occurs under normal use

SHIMANO STEPS

W = warning (ride OK) E = error (assist stops)

Code	Meaning	First check
W011	Speed sensor no signal	Check spoke magnet & sensor alignment; confirm magnet is secure
W013 / E012	Torque sensor not initialized	Restart with both feet completely off pedals — most common cause
E010	General drive unit fault	Restart first; if persistent, drive unit requires inspection
E011	Internal drive unit error	Power cycle; document frequency — persistent = drive unit failure
W014	Battery comm warning	Reseat battery firmly; clean contact pins with dry cloth
E015	Battery comm error — assist stops	Check battery contacts & cable; try known-good battery

Shandoka Cycles Certification — Module 2 Bench Reference | Error codes vary by firmware version — always verify with manufacturer documentation when in doubt For codes not listed: search brand + model + code · Call manufacturer help desk · Build a relationship with a specific support rep — your best resource for unlisted codes