W 101 error means that the riding speed is not detected.
Also common error codes for the seam reason are: W011 or E014
While the error is displayed your riding experience can change and become very distant from the real deal of riding an eBike. The maximum speed up to which support is provided may be less than usual due to this error. Which means that if you normally reach 16 mph (25 km/h) the motor assistance shuts down due to regulations of the factory. But due to this error the speed at which motor turns off the speed assistance functions may vary a lot. This means that your motor assistance can differ even into speeds like 10 mph where your assistance will turn itself off.
Fixing the issueCheck whether the speed sensor is installed correctly and the spoke magnet is in the correct position. The distance from the speed sensor (observe the markings) on the chainstay to the spoke magnet should be between 3 and 17 mm.
Problem occurrenceThis problem may vary in its wake; it could be physical damage or lack of care for the ebike.
Most common of this error is the issue of water, sludge or any other residue buildup in the sensor - motor areas. This is not an expensive part to change so the repairs are necessary, furthermore keep in mind that your ebike always requires the same level of care like any other travel gear. So don’t forget to use the best products suited for your ebike care and protection. Bike chains and all the other parts that move very easily require constant lubrication and cleaning, in case of dirt buildup and no care for these parts, they can easily break and damage other vital parts of your e-bike!