What goes wrong on electric bikes, scooters and e-mopeds, and the first thing to check for each. It's written by the people who wrote the certification course, and it's free.
Measure at the source, then follow the chain: battery, connection, controller, motor, wheel. The first place the answer is "no" is where your problem is. Check the cheap, likely causes first. Ordering a controller for a sticky brake lever makes for a bad afternoon.
Check the brake levers first. Most electric bikes have a cutoff sensor in each lever that kills motor power the moment you brake. A lever that doesn't return fully, from a sticky pivot, a bent lever or a binding cable, leaves that sensor permanently triggered. The controller thinks you're braking forever, so the motor never runs. It's the most commonly missed diagnosis in this trade, it costs nothing to rule out, and on many systems it also throws an E02 code.
That's almost always a connector. On round Julet or Higo connectors the locking collar has to be threaded fully down. Half-engaged, the pins still touch on the stand but separate for a few milliseconds over a pothole. Go around the whole vehicle by hand and seat every collar before you suspect the controller.
Measure the battery with a meter instead of trusting the indicator lights. A pack can show four bars and still sit below the voltage the controller needs, and a pack whose protection circuit has tripped can read full while delivering nothing. Then follow the chain in order: battery, the connection to the controller, the controller, the motor.
An error code usually tells you what the controller can't talk to, which isn't always what's broken. Write the code down, power off, reseat every connector in that system, and power back on. A surprising number clear right there. Then look the code up.
Two ordinary explanations. The pack may be aging, sagging under load in a way a resting voltage check won't show. Or the controller's speed or power settings were changed by an owner, a previous technician or a firmware update. You can measure both.
Stop. Do not charge it, and do not bring it indoors. A pack that took an impact can enter thermal runaway hours or days later while looking undamaged, so it gets stored outdoors or in a fireproof container, the customer gets told, and the finding goes in writing. This is the one place in the trade where there's no judgment call.
Check the pads before the cable. Below 1 mm of pad material they get replaced, full stop. Tension the cable against worn pads and the lever feels better right away. That's the trap: you've added no braking material, and the rider now wears through that last millimeter faster.
Yes, and most people who take this course start with none. You need ordinary high-school math and science, somewhere to practice, and about 13 hours of reading plus 15-20 hours of bench work. The first module is free to read, so you can find out whether the material suits you before paying anything.
People forget the steps for a swollen, hot or damaged lithium pack at the worst possible moment. Our battery fire safety poster puts them on the wall, and anyone can order one. Ask us for a poster.
The Shandoka technician certification starts from zero experience and covers e-bikes, kick scooters, e-mopeds and electric motorcycles. It's about 13 hours of reading plus bench time, and Module 1 is free to read, so start there and decide for yourself.
Running a shop? Training a whole team works differently, with seats, records and a guide for handing bench work over safely.
