Home › Diagnosis › KT LCD3, LCD8, S866, S830 and SW900 reset: safe default P and C parameters, service codes and what to write down first
Generic LCD (KT, S866, SW900) reset: restore defaults without ruining your bike
ResetsKT LCD3/LCD8, S866/S830, SW900
Most budget and mid-range e-bikes use a KT (Kunteng) controller with an LCD3, LCD5, LCD8 or a King-Meter S866 / S830 / SW900 display. The 'reset' on these is a parameter reset in the settings menu. Get the parameters right and the bike is as new; get P1 or C1 wrong and it will not assist at all. Write everything down first.
Warning: There is no undo on these displays. A 'restore defaults' (LCD3: C10) loads the display's generic defaults, not your bike's factory values, so speed limit, wheel size, PAS type and current limit may be wrong afterwards. Photograph every P and C page before you change anything. A defaults reset also zeroes the display odometer. No parameter change clears a genuine error (E-codes like 06, 07, 08, 09, 30): those are hardware.
What you need
- Battery above 20%
- Photos of every settings page before changing anything
- Wheel size from the tyre sidewall (e.g. 26, 27.5, 28/700C, 20)
- Knowledge of your PAS sensor type (KT 12-magnet disc = C1 02; other brands see below)
Step by step
1. Soft reset and power cycle
Hold the power button to switch off, wait 5 seconds, switch on. If the error stays: battery out 30 seconds, check the display cable and the controller's connectors, refit, switch on.
If OK: Error gone.
If not: Error stays: E06/E07 battery voltage, E08/E09 hall/phase, E30 communication. Go to the generic error code page. The rest of this flow fixes settings, not faults.
Hold the power button to switch off, wait 5 seconds, switch on. If the error stays: battery out 30 seconds, check the display cable and the controller's connectors, refit, switch on.
If OK: Error gone.
If not: Error stays: E06/E07 battery voltage, E08/E09 hall/phase, E30 communication. Go to the generic error code page. The rest of this flow fixes settings, not faults.
2. What to write down first
Enter the settings (see next step) and photograph every page: P1–P5 and C1–C14 on LCD3/LCD8; P01–P20 on S866/S830; the settings list on SW900. Also write the current ODO, the speed limit, wheel size and the number of assist levels (3, 5 or 9).
If OK: You have a record you can restore from.
If not: Skipped this and the bike now behaves differently: use the safe defaults below and adjust from there.
Enter the settings (see next step) and photograph every page: P1–P5 and C1–C14 on LCD3/LCD8; P01–P20 on S866/S830; the settings list on SW900. Also write the current ODO, the speed limit, wheel size and the number of assist levels (3, 5 or 9).
If OK: You have a record you can restore from.
If not: Skipped this and the bike now behaves differently: use the safe defaults below and adjust from there.
3. Enter the settings menu
KT LCD3/LCD8: bike on, hold UP and DOWN together about 2 seconds for P settings; from P5 press UP+DOWN again to reach C settings. S866/S830: hold UP and DOWN 2 seconds (some ask for a password: 8018 is the widely published one; some use 1919 or 0512). SW900: hold UP and DOWN 2 seconds; many builds have no password, some use 0000. Move with UP/DOWN, confirm with the power/M button.
If OK: Menu open.
If not: Password unknown: try the published codes once each; if none works, the brand set a custom one and only the seller or their support has it.
KT LCD3/LCD8: bike on, hold UP and DOWN together about 2 seconds for P settings; from P5 press UP+DOWN again to reach C settings. S866/S830: hold UP and DOWN 2 seconds (some ask for a password: 8018 is the widely published one; some use 1919 or 0512). SW900: hold UP and DOWN 2 seconds; many builds have no password, some use 0000. Move with UP/DOWN, confirm with the power/M button.
If OK: Menu open.
If not: Password unknown: try the published codes once each; if none works, the brand set a custom one and only the seller or their support has it.
4. KT LCD3 / LCD8 P parameters: safe defaults
P1 = motor gear ratio × magnet count (typical geared hub 87, direct drive 46; keep whatever it was); P2 = speed sensor signals per revolution (1 for most hubs with an external sensor; 0 or 6 for internal); P3 = 1 (assist by speed) or 0 (assist by current; choose what it was); P4 = 0 (throttle works from standstill) or 1 (only after pedalling); P5 = battery indicator calibration (leave as is; typical 12–15 for 36 V, 4–11 for 48 V). Wheel size and speed limit are set separately in the P menu on most firmware; put the real wheel size in.
If OK: Speed reads right, assist responds.
If not: Speed wildly wrong: wheel size or P2. No assist at all: P1 or C1.
P1 = motor gear ratio × magnet count (typical geared hub 87, direct drive 46; keep whatever it was); P2 = speed sensor signals per revolution (1 for most hubs with an external sensor; 0 or 6 for internal); P3 = 1 (assist by speed) or 0 (assist by current; choose what it was); P4 = 0 (throttle works from standstill) or 1 (only after pedalling); P5 = battery indicator calibration (leave as is; typical 12–15 for 36 V, 4–11 for 48 V). Wheel size and speed limit are set separately in the P menu on most firmware; put the real wheel size in.
If OK: Speed reads right, assist responds.
If not: Speed wildly wrong: wheel size or P2. No assist at all: P1 or C1.
5. KT LCD3 / LCD8 C parameters: safe defaults
C1 = PAS sensor type: 02 for the KT 12-magnet disc (00–02 for standard, 05–07 for other sensor types; keep the original); C2 = 0 (motor phase, leave); C3 = assist level at start-up (0–5 fixed, or 8 = remember last level); C4 = throttle behaviour (0 throttle always, 1 only after PAS; check local law); C5 = current limit (10 = maximum, lower reduces power; 10 is the usual factory value); C6 = backlight 3; C7 = cruise 0; C8 = motor temperature display 0; C9 = start-up password 0 (off); C10 = restore defaults (y/n) — this is the actual reset; C11 = service (0); C12 = low-voltage cut-off (4 = factory); C13 = regenerative braking 0; C14 = PAS response 2 (medium).
If OK: Bike behaves like new; adjust C5 and C14 to taste.
If not: Still no assist after correct C1: PAS sensor magnet ring or sensor gap (1–3 mm). Not a settings problem.
C1 = PAS sensor type: 02 for the KT 12-magnet disc (00–02 for standard, 05–07 for other sensor types; keep the original); C2 = 0 (motor phase, leave); C3 = assist level at start-up (0–5 fixed, or 8 = remember last level); C4 = throttle behaviour (0 throttle always, 1 only after PAS; check local law); C5 = current limit (10 = maximum, lower reduces power; 10 is the usual factory value); C6 = backlight 3; C7 = cruise 0; C8 = motor temperature display 0; C9 = start-up password 0 (off); C10 = restore defaults (y/n) — this is the actual reset; C11 = service (0); C12 = low-voltage cut-off (4 = factory); C13 = regenerative braking 0; C14 = PAS response 2 (medium).
If OK: Bike behaves like new; adjust C5 and C14 to taste.
If not: Still no assist after correct C1: PAS sensor magnet ring or sensor gap (1–3 mm). Not a settings problem.
6. Restore defaults (LCD3 C10 / S866 'Default' / SW900 'Reset')
LCD3/LCD8: go to C10, set to 'y', hold the power button to confirm; the display restarts with generic defaults. S866/S830: settings item 'Default settings' or 'Restore' › confirm. SW900: 'Reset'/'Default' item near the end of the list. AFTER the reset re-enter wheel size, speed limit, P1, P2 and C1 from your photos.
If OK: Clean parameter set; problems caused by a previous owner's tuning are gone.
If not: Values reverted to something that does not match the bike (typical: wheel size 26 on a 28-inch bike, speed limit 25 on a 20 mph US bike, C1 wrong): correct them from your photos.
LCD3/LCD8: go to C10, set to 'y', hold the power button to confirm; the display restarts with generic defaults. S866/S830: settings item 'Default settings' or 'Restore' › confirm. SW900: 'Reset'/'Default' item near the end of the list. AFTER the reset re-enter wheel size, speed limit, P1, P2 and C1 from your photos.
If OK: Clean parameter set; problems caused by a previous owner's tuning are gone.
If not: Values reverted to something that does not match the bike (typical: wheel size 26 on a 28-inch bike, speed limit 25 on a 20 mph US bike, C1 wrong): correct them from your photos.
7. S866 / S830 and SW900 specifics
S866/S830 items are numbered P01–P20 (P01 backlight, P02 units, P03 voltage 24/36/48, P04 auto-off time, P05 PAS level count, P06 wheel size, P07 speed magnet count, P08 speed limit, P09 zero-start, P10 drive mode, P11–P13 PAS sensitivity/start/magnets, P14 controller current limit, P15 cut-off voltage, P16 ODO reset (hold to zero), P17 cruise, P18 speed ratio, P19 zero-level PAS, P20 comms protocol). SW900: wheel size, speed limit, voltage, PAS level count, P-type items, then 'Reset'. Set P03/voltage to your battery's nominal voltage: a wrong voltage setting makes the battery gauge lie and can trigger a low-voltage cut.
If OK: Gauge and speed correct.
If not: Bike cuts out on hills: P14 current limit or P15 cut-off too high. Restore the original values.
S866/S830 items are numbered P01–P20 (P01 backlight, P02 units, P03 voltage 24/36/48, P04 auto-off time, P05 PAS level count, P06 wheel size, P07 speed magnet count, P08 speed limit, P09 zero-start, P10 drive mode, P11–P13 PAS sensitivity/start/magnets, P14 controller current limit, P15 cut-off voltage, P16 ODO reset (hold to zero), P17 cruise, P18 speed ratio, P19 zero-level PAS, P20 comms protocol). SW900: wheel size, speed limit, voltage, PAS level count, P-type items, then 'Reset'. Set P03/voltage to your battery's nominal voltage: a wrong voltage setting makes the battery gauge lie and can trigger a low-voltage cut.
If OK: Gauge and speed correct.
If not: Bike cuts out on hills: P14 current limit or P15 cut-off too high. Restore the original values.
8. Widely published service codes (use with care)
8018 (S866/S830 and many KM displays), 1919 and 0512 (older Bafang/KM units), 0000 (some SW900), 2020/2021 (some brand builds). These only open the menu; they do not clear errors or unlock anything hidden. Changing the speed limit above your country's limit makes the bike illegal and can void insurance.
If OK: Menu opened, one value adjusted, tested.
If not: None work: brand-specific code. Ask the seller or brand support; do not buy 'unlock cables' for a KT display, they are unnecessary.
8018 (S866/S830 and many KM displays), 1919 and 0512 (older Bafang/KM units), 0000 (some SW900), 2020/2021 (some brand builds). These only open the menu; they do not clear errors or unlock anything hidden. Changing the speed limit above your country's limit makes the bike illegal and can void insurance.
If OK: Menu opened, one value adjusted, tested.
If not: None work: brand-specific code. Ask the seller or brand support; do not buy 'unlock cables' for a KT display, they are unnecessary.
What you now know for sure
- Transient: Gone after off/on or power cycle. → Nothing to do.
- Wrong parameters: Speed, assist or gauge wrong; fixed by re-entering wheel size, voltage, P1/P2/C1. → Photograph the working settings and keep them with the bike.
- Defaults applied wrong: After a reset the bike behaves worse. → Re-enter the photographed values; if you have none, use the safe defaults above and test one change at a time.
- PAS / sensor hardware: Correct C1 and still no assist. → Check PAS magnet ring gap and cable; replace the sensor (cheap).
- Error code: E06–E09, E30 or similar stays. → Generic error code page; controller, battery or motor wiring.
Manuals and video
These displays are sold unbranded by many factories, so there is no single official manual. Check the manual that came with your bike, or your bike brand's support page.
Videos found on YouTube and checked automatically; they are other people's work, not ours.
Frequently asked
What is the reset code for a KT LCD3?
There is no code. Hold UP and DOWN to enter the P menu, press UP and DOWN again from P5 for the C menu, and set C10 to 'y' to restore defaults. Photograph your settings first.
Does restoring defaults reset the odometer on an S866 or SW900?
Yes, on most King-Meter displays the ODO is in the display and a defaults reset zeroes it. S866 also has a separate P16 ODO reset. That is why 'low km' on a KT bike proves little.
Which PAS type (C1) should I use?
Keep the original value. If it is lost: the common KT 12-magnet disc sensor is C1 = 02. If assist only works backwards or not at all, try 00–02 first, then 05–07. Do not change C2 (phase).
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.