Home › KT / Kunteng LCD › Error 30
KT / Kunteng LCD error 30: Communication abnormality
KT / Kunteng controllers with LCD3, LCD5, LCD8, LCD8H displays (generic hub-motor kits and budget e-bikes)Fix at homeRide with caution
The KT display and controller are not exchanging data. The display may power on with no speed or battery data, freeze, or show 30 straight away. Nearly always a connector, harness or protocol mismatch problem.
Likely causes
- Display connector loose, wet or with a bent pin
- Damaged wire in the display cable or main harness
- Display not matching the controller (KT displays only work with KT controllers using the same protocol)
- Wrong display cable pinout after a replacement (5-pin colours do not match)
- Controller communication port damaged
How to fix KT / Kunteng LCD error 30
- Switch off, unplug the display, check for water and bent pins, clean and re-seat
- Wiggle the cable with the bike on: intermittent data means a broken wire
- Confirm the display is a KT model matching the controller protocol
- Verify the pinout (power, ground, TX, RX, key) if the cable was replaced
- Try a known-good KT display or replace the display cable; if still 30, replace the controller
Go to a dealer if: Go to a shop if a matching known-good display still shows 30.
Warranty: Budget kits and bikes usually have 1 year of seller warranty; contact the seller before opening the controller or motor.
Typical cost: Display cable EUR/USD 10-20; KT LCD EUR/USD 30-80; controller EUR/USD 40-90.
Warranty: Budget kits and bikes usually have 1 year of seller warranty; contact the seller before opening the controller or motor.
Typical cost: Display cable EUR/USD 10-20; KT LCD EUR/USD 30-80; controller EUR/USD 40-90.
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
How do I reset KT error 30?
Re-seat the display connector and power cycle.
Can I keep riding?
Pedal home yes; assist is normally blocked.
Warranty?
Yes for a display or controller port failing early.
Related KT / Kunteng LCD codes
Not an official KT / Kunteng LCD document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.