Why is the car weak and slow after replacing the controller?

[RichardLee]

Replacing the controller may result in a weak and slow car due to a damaged throttle grip, low battery, poor connection, issues with the ignition lock, accidental speed limitation (maximum around 20 km/h), a faulty motor Hall sensor, or motor problems. Methods to check for power loss after replacing the controller are as follows: Method 1: Check if the battery is sufficiently charged. If the battery is normal but the speed is very slow, with a maximum of around 20 km/h, it may be speed-limited. Method 2: Try replacing the throttle grip. If the car starts abnormally, shakes violently, and lacks power, check if the motor wires are burnt and test whether the Hall sensor is damaged.