Start with observation and documentation. These checks help you explain a problem to qualified support; they do not diagnose an electrical component or replace your model-specific manual.
The bike will not turn on
Record the model and display, what happens when you use the documented power control, and the last time it worked normally. Check the normal startup sequence in the confirmed manual. Do not bypass wiring, bridge terminals or assume the battery is faulty.
The charger or battery behaves unexpectedly
Record the charger and battery labels and any visible indicator behavior. Stop using or charging damaged equipment. Obtain model-specific support before trying a different charger or battery; do not open the pack.
The display shows an unfamiliar code
Photograph the exact code and display model. Record whether it appears at startup, under assist or after another event. Use the confirmed display guide; the same code can mean different things on different controllers.
The brakes, steering or folding mechanism feel wrong
Stop riding and have the bike checked by a qualified person. Do not continue a test ride to see whether a safety-critical fault clears. Ask for the correct inspection and service instructions for your model.
A concise message gets a clearer answer
“My model is [full label]. It was purchased from [seller] on [date]. The symptom is [what happens], starting [when]. The display shows [exact text]. I have followed [documented user checks]. Please confirm the correct manual and next diagnostic step.” Send order details privately.
Use the supplied or manufacturer-recommended charger. Stay present while charging and do not charge while sleeping. Follow the manufacturer’s instructions and stop using damaged equipment.
Find a manual source · Before buying a replacement · Find the responsible seller
Sources & review notes
Reviewed November 10, 2026. These are published-source notes, not hands-on testing. Listings and policies can change; check the current document and your exact bike before acting.