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KT / Kunteng LCD error 25: Brake abnormality

KT / Kunteng controllers with LCD3, LCD5, LCD8, LCD8H displays (generic hub-motor kits and budget e-bikes)Fix at homeRide with caution

The controller sees a permanent brake cut-off signal. The bike rolls and the display works, but there is no assist and no throttle. Typically caused by a brake lever or sensor that never releases.

Likely causes

Brake lever pulled at power-up
Brake sensor magnet misadjusted or stuck
Damaged brake sensor cable
Wrong brake sensor type for the controller (normally open vs closed)
Water in the brake sensor connector

How to fix KT / Kunteng LCD error 25

Power cycle without touching the brakes
Check both levers return fully; adjust the sensor magnet
Unplug one brake sensor at a time to find the faulty one
Dry and clean the connectors
Replace the faulty brake sensor; if the code stays with both unplugged, the controller input is faulty

Go to a dealer if: Go to a shop if the code persists with both brake sensors unplugged.
Warranty: Budget kits and bikes usually have 1 year of seller warranty; contact the seller before opening the controller or motor.
Typical cost: Brake sensor EUR/USD 5-20; usually free by adjusting the lever.

Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.

Frequently asked

Can I reset error 25?

Power cycle with the brake levers released.

Can I keep riding?

Yes without assist; the bike is otherwise safe.

Warranty?

Rarely; brake sensors are cheap parts.

Related KT / Kunteng LCD codes

22 · Throttle abnormality

Not an official KT / Kunteng LCD document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.