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Brake cutoff sensor

The brake cutoff sensor tells the controller you are braking so it cuts motor power. A stuck one can stop the motor. Replace it like for like and never bypass it.

Last edited Nov 8, 2026 by Pedalwise team Edit History Add a subpage

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A brake cutoff sensor tells the controller when a brake lever is pulled. Grin Technologies explains that it serves as a safety cutoff that shuts off the motor while you brake, and on some hub systems it also switches on regenerative braking. The switch can be built into a mechanical or hydraulic lever, or added to an existing brake (Grin, e-bike parts explained).

The brake cutoff is a safety feature. Never bypass it, unplug it to get the motor running, or ride with it disconnected. Replace a faulty sensor with one made for your system, plugged in at its connector, and remove the battery first.

What it's used for

Because the cutoff shuts the motor off, a sensor that is stuck, misaligned or damaged can leave the bike with no throttle or assist. Check it with Check brake cutoff and throttle, and see Motor cuts out, Throttle not working and No pedal assist.

What to look for

  • Built into the lever or add-on. California Ebike sells Bafang mechanical e-brake levers with the switch built in, a pair of Bafang hydraulic brake sensors, and a hidden wire brake sensor (California Ebike brakes). Match the style your bike uses.
  • Mechanical or hydraulic brakes. Sensors for hydraulic brakes are sold separately from those for cable brakes (California Ebike brakes).
  • The plug for your system. The sensor must plug into your controller or harness. Bafang listings are sold by system, so buy the one for yours, and check with the seller when a listing doesn't say (California Ebike cables and sensors).
  • Plain levers don't have it. Rad Power Bikes sells Tektro mechanical levers, and its listing does not mention a sensor (Rad brake lever). Check whether your old lever has a sensor cable before you order. See Brake lever.

Typical price

  • California Ebike lists Bafang hydraulic brake sensors at $29.95 a pair (read Nov 9, 2026) (California Ebike).
  • California Ebike lists the Bafang hidden wire brake sensor at $19.95 (read Nov 9, 2026) (California Ebike).
  • California Ebike lists Bafang mechanical e-brake levers at $10 a pair (read Nov 9, 2026) (California Ebike).

Where to buy

  1. Your bike maker's parts store or support team.
  2. For Bafang systems, a Bafang service center such as California Ebike.
  3. Independent specialists in Where to buy e-bike repair parts.
  4. A local shop, through find a shop.

Videos

Adjusting a Motor Shutoff Brake Sensor from Alter Ego Electric Bikes: An e-bike shop repositions the magnet and sensor on a brake lever so the motor cuts out only when the brake is pulled.
Error 25: Brake Sensor Error, Ride1UP from Ride1Up: The bike maker explains what its brake sensor error means and how to check the sensors and their plugs.

Guides that use it

Sources

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Guides that use this

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