Heybike Cityrun, Tyson, Ranger S and Mars 2.0: error 25, bike won't accelerate

Your Heybike powers on and the display works, but the bike won't accelerate and error 25 shows. Error 25 is a brake failure code on the Cityrun, Tyson, Ranger S and Mars 2.0, among a few other models (Heybike error codes). The brake levers carry cut-off sensors that stop the motor when you brake. If one is stuck on, the controller thinks you are braking all the time. Short answer: a lever that hasn't fully returned or a cut-off sensor that needs adjusting or replacing.

Most likely cause

The first step is simply to confirm that the left and right brakes have returned to their normal position (Heybike error codes). A lever that sticks, a bent lever, or a grip or bag pressing on it holds the sensor in the braking position. Brakes being engaged also stop a bike from powering up properly (Heybike common problems). On hydraulic brakes, the sensor sits at the lever and can drift out of adjustment.

Other causes to rule out

• A loose or damaged cable at the brake or throttle plugs. The second step is to check connections there for seating, bent pins, arrow alignment and broken wires (Heybike error codes).
• A faulty brake lever or cut-off sensor, found by unplugging one side at a time.
• A failed controller, the last suspect once the brakes check out.

How to confirm

1. Power off. Squeeze and release each brake lever several times and check that each springs fully back. Move any bag, mirror or grip that touches a lever.
2. Power on with your hands off both levers. If error 25 is gone, the lever was being held.
3. Power off and check the plugs for both brake levers and the throttle. Reseat each one with the arrows lined up (Heybike error codes). See inspect and clean connectors.
4. Power off, unplug the left brake connector, then power on. Repeat with the right side. If the error disappears with one side unplugged, that brake is faulty (Heybike error codes). Plug it back in before riding.
5. Check that the motor stops when you pull each lever once everything is reconnected. Our guide to checking the brake cut-off and throttle walks through this.

Fix options

Free up or straighten the lever (easy)

Clean around the pivot, move whatever is pressing it, and make sure it returns on its own. If the lever is bent from a fall, replace it.

Adjust the hydraulic lever sensor (easy to moderate)

For hydraulic brakes, turn the fixed screw at the bottom of the brake lever, which sets the power cut-off sensor, counterclockwise by half a turn (Heybike error codes). Afterwards, confirm that the motor still cuts out as soon as you pull that lever. If it doesn't, undo the change and get the sensor replaced.

Replace the brake lever (moderate)

For mechanical brakes, replace the faulty brake (Heybike error codes). Get the matching lever from Heybike for your model, because lever length and connector differ between models. A shop can fit and adjust it, including the brake cable.

Replace the controller (pro or Heybike support)

Only if every brake checks out is the controller the suspect (Heybike error codes). Have a shop confirm this first.

Parts

• Brake lever
• Brake cutoff sensor
• E-bike controller

Videos

When to get a pro

Get help if the lever feels soft, the brake drags, or the motor does not cut when you brake after a fix. Brakes are not a place to guess. See e-bike brakes and Heybike troubleshooting.

Sources

• Heybike error codes, heybike.zendesk.com
• Heybike common problems, heybike.zendesk.com
• Error 25: Brake Sensor Error: Ride1UP, youtube.com
• Adjusting a Motor Shutoff Brake Sensor, youtube.com

Stuck after these checks? Find a shop near you.