KT displays, made by Kunteng, are everywhere in the aftermarket. If your bike came from a smaller brand, or if someone has already fitted a replacement kit, there is a good chance the screen in front of you is a KT-LCD3 or one of its siblings. The codes it shows are not the same numbering other brands use, so a table from a different display will send you looking at the wrong part.
Here is what the KT codes mean, where each one is genuinely defined, and what the code is pointing you at.
The five codes the official manual defines
01 — Throttle fault. The display is seeing a throttle signal that is out of range, most often because the throttle is not returning to rest. Check that it springs back all the way, unplug and reseat the connector, and look for water inside it. A throttle that has been sitting under a hose or through a wet winter is the usual culprit, and it is a cheap part to replace.
03 — Motor hall signal fault. The controller is not getting clean hall signals from the motor. Start at the nine-pin motor connector rather than at the motor, because a bent or corroded pin looks exactly like a dead sensor from the display's point of view. If the connector is sound, the hall sensors themselves can be tested. Our guide to phase and hall wiring colours covers which wires you are looking at.
04 — Torque sensor signal fault. Only applies to bikes fitted with a torque sensor. Realign the sensor to its magnet ring, keep the gap in the one to two millimetre range, and clean the ring before assuming the sensor has failed.
05 — Axle speed sensor fault. Found on the torque-sensor versions. Check the motor cable and the alignment of the speed magnet, which can drift after a wheel has been out.
06 — Motor or controller short circuit. This is the one to take seriously. Disconnect the battery before doing anything else. Look at insulation and at the phase wires for damage or a pinched section. If the code returns after a reconnection, stop powering the bike up and diagnose it disconnected. Repeatedly energising a short is how a controller fault becomes a burnt harness.
What about 02 and 07?
You will find tables online that assign meanings to KT codes 02 and 07. We could not find either code defined in the official KT-LCD3 manual, so we are not going to invent one. If your display shows a code that is not in the list above, treat it as unidentified and diagnose by symptom instead of by code. Guessing at a code's meaning is how the wrong part gets ordered.
Codes that come from third-party sources, not the manual
Two more groups circulate widely and are worth knowing about, with the caveat that they come from repair write-ups rather than from the official documentation. Codes reported as E08, 009 or 37 are described as an internal controller fault; a hard reset, meaning battery off for ten to fifteen minutes, is worth trying before anything else, and a controller that keeps reporting it is a controller to replace. Codes reported as E10, E11 or 30 are described as a display-to-controller communication failure. There the cable and both connectors come first, and if a part has to be replaced, the display is the cheaper end of that conversation to try.
That last group overlaps with something we have written about before: 30 as a communication error appears across a whole family of brands that build on the same upstream controller platform, which we covered in our piece on the shared 21-to-30 code family.
The compatibility trap behind communication codes
A communication error on a KT display very often is not a failure at all. It is a mismatch. KT displays speak the KT protocol and pair with KT controllers; drop one onto a controller from a different platform and the two will not talk, no matter how well the connector fits. Connector shape is not protocol. If the code appeared right after someone swapped a display or a controller, that is where to look first, and we go through the whole problem in why a new display often will not work with your controller.
Getting from a code to a part
Every code above names a circuit, not a verdict. Codes 01, 03, 04 and 05 all point at a sensor or its wiring, and in each case the connector is more likely to be at fault than the component behind it. Unplug it, look at the pins, reseat it, and re-test before buying anything. A meter at the connector will tell you whether signal is arriving, and that one measurement decides which part actually needs replacing. Code 06 is the exception: it is a safety code, and the correct first move is to remove power, not to keep testing.
Write the number down, note whether it appears constantly or only under load, and work the free checks first. Most KT codes are describing a connection, and the ones that are not will still be waiting once the connections have been ruled out.