The TMM sensor in the right chainstay is the crucial component when it comes to drive assistance for electric bikes. If something is wrong with the sensor, it becomes immediately noticeable in the assistance.
ID Bike, the manufacturer, has improved the design of the sensor plate and the sensor in several ways during model development. For example, these and the supply cable have been completely potted. The slot width, which allows for movement variation, has been massively increased and is less susceptible to dirt. The mechanical adjustment elements of the magnet have also been completely removed, and the magnet has been glued into the plate.
Die Sensorelektronik (Hallelement) ist gegen Schmutz geschützt. Trotzdem ist dieser eine mögliche Fehlerquelle, da er sich rund um den Magneten ablagern kann oder die Messausfräsung auffüllt, und somit die Messung der Ketten- bzw. Riemenkraft beeinflussen kann.
The reason for this grime is the operation of the vehicle, but also incorrect lubrication of the chain. The chain oil, the fine metallic abrasion from the chain and sprockets, and street dirt combine to form a sticky, sometimes coked emulsion that can completely „glue“ the sensor. The iron particles can interfere with the magnet and thus the force measurement, leading to fluctuations in assistance or even a complete failure.
Cleaning
For cleaning, you should remove the rear wheel. You may not use metallic, pointed, or sharp objects as cleaning tools. It is best to use a fine brush or a toothbrush, as well as cleaning paper – and if available, compressed air – to remove all dirt. Use brake cleaner, cleaning gasoline, or a degreasing bicycle cleaner as cleaning agents.
If you have a cleaning bath, you can also remove the sensor, clean it inside, and then carefully blow it out with compressed air. I would not recommend an ultrasonic bath, as this could damage the sensor.
The Installation des Sensors ist here described.