Diagnose e-bike and e-moto faults by symptom. Won’t start, short range, weak power, noisy motor or soft brakes — find the likely cause and the parts that fix it.
Most no-start faults trace to the battery, the BMS cutting out, a loose main connector, or the controller. Check the battery is charged and seated, then inspect the main power connector before replacing parts.
Range loss is usually cell ageing, cold weather, low tyre pressure, or riding in a higher assist mode. A battery that has lost a large share of its original range is likely near the end of its useful life.
Grinding or whining usually points to worn bearings, a dry or worn chain and sprocket, or loose motor mounts. Mid-drive motors also make noise when the chainline is misaligned.
A spongy lever normally means air in a hydraulic line or worn pads. Bleed the system and check pad thickness before replacing the caliper.