King-Meter error 03: Pedal assist sensor signal problem
The display has lost a normal reading from the pedal assist sensor (PAS), the small sensor by the bottom bracket that counts crank rotation. As a result the controller usually cuts motor assistance, walk assist stops working and the assist level indicator behaves erratically. The bike still powers on and lights still work, but pedalling no longer produces motor help until the fault is cleared.
| Drive system | King-Meter K5242 / KM5S LCD display |
| Severity | Fix at home |
| Keep riding? | Ride with caution |
| Typical cost | A PAS sensor replacement typically runs 25 to 60 EUR for the part plus 40 to 80 EUR labour at a dealer, while a simple harness repair or connector service usually falls between 20 and 50 EUR. |
Likely causes
- PAS connector loose, not fully seated or pulled apart at the sensor or controller end
- Cable pinched, chafed or cut where it runs along the down tube or near the motor
- Moisture or green corrosion inside the PAS connector after riding in rain or a wash
- Magnet ring (PAS disc) misaligned, loose on the crank or missing magnets
- PAS sensor itself failed internally
- Controller input for the PAS signal damaged
How to fix King-Meter error 03
- Switch off the display and remove the battery before touching any wiring.
- Locate the PAS sensor on the left side of the bottom bracket and follow its cable to the controller housing.
- Unplug the PAS connector at both ends and inspect the pins for bending, dirt or moisture.
- Clean any corroded pins with contact cleaner or isopropyl alcohol, let them dry, then reconnect firmly so the latch clicks.
- Check the magnet disc on the crank for missing magnets, correct spacing to the sensor (usually 1 to 3 mm) and a tight fit on the axle.
- Refit the battery, power the bike on and ride a short loop to confirm whether 03 has cleared.
- If the code returns, stop DIY work and take it to a shop for PAS sensor replacement or controller input testing.
Warranty: A genuine PAS sensor or wiring failure inside the two-year warranty window is normally treated as a manufacturer defect and covered, while crash damage, water ingress and worn magnet discs are usually excluded.
Typical cost: A PAS sensor replacement typically runs 25 to 60 EUR for the part plus 40 to 80 EUR labour at a dealer, while a simple harness repair or connector service usually falls between 20 and 50 EUR.
Frequently asked
Can I reset king-meter error 03?
Switching the bike off and back on, or pulling the battery for about a minute, may clear the code if it was a momentary signal glitch. The code returns on the next ride if the sensor signal is still bad. A reset without fixing the cause does not hold.
Is it safe to keep riding with this error?
Pedalling without assistance is safe on flat ground for a short trip home or to a workshop. Avoid steep climbs, because the motor will not help when you expect it. Clear the fault before returning to normal use.
What does the repair cost and is it covered by warranty?
Expect 25 to 60 EUR for the sensor and 40 to 80 EUR labour if a dealer handles it. On a bike under two years old with a sensor that failed on its own, most manufacturers cover the part. Crash, water and worn magnet ring cases are normally billed to the owner.
Related King-Meter codes
Official source: King-Meter K5242 LCD manual, appendix 1 Error Code Definition
Not an official King-Meter document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.