King-Meter error 08: Motor hall sensor signal abnormal
The display has lost the feedback signal from the hall sensors mounted inside the hub motor, which the controller needs to know the rotor position before it can drive the motor. As a result the controller cuts motor assist, the throttle and walk assist stop working, and the speed reading may stay at zero or jump around erratically. Power to lights and the display itself is unaffected, but the bike will only roll under leg power until the fault is fixed.
| Drive system | King-Meter K5242 / KM5S LCD display |
| Severity | Dealer needed |
| Keep riding? | Do not keep riding |
| Typical cost | Plan on roughly 20 to 60 EUR for a replacement motor loom and connector, 80 to 150 EUR for an internal hall sensor job on a hub motor, and 60 to 150 EUR for a new controller if diagnosis points that way, plus workshop labour. |
Likely causes
- Loose, dirty, or corroded motor cable connector at the controller or motor axle
- Water ingress into the motor cable junction or controller plug
- Broken, pinched, or chafed phase or hall signal wire between controller and motor
- Failed hall sensor inside the hub motor
- Controller unable to read a valid hall signal even though the wiring is intact
How to fix King-Meter error 08
- Switch the battery off and remove the key before any inspection.
- Unplug the motor cable at the controller and at the axle, check the pins for corrosion, bent contacts, or moisture, then refit both ends firmly.
- Inspect the motor cable along its full run for cuts, kinks, or pinch damage near the dropout or controller housing.
- If your controller exposes a hall test outlet, power the system on (with the battery isolated from the wheels) and check the hall signal with the procedure in the controller manual; otherwise measure continuity and insulation of the phase line running from controller to motor.
- Replace the motor cable or the controller if the wiring tests good but the controller still flags 08.
- Have a dealer open the hub and replace the internal hall sensor board if the fault follows the motor across a known-good cable and controller.
Warranty: A genuine hall sensor or motor wiring failure inside the first two years is normally treated as a manufacturer fault and covered, while water ingress, crash damage, and corroded connectors from poor storage are usually excluded.
Typical cost: Plan on roughly 20 to 60 EUR for a replacement motor loom and connector, 80 to 150 EUR for an internal hall sensor job on a hub motor, and 60 to 150 EUR for a new controller if diagnosis points that way, plus workshop labour.
Frequently asked
Can I reset king-meter error 08?
No power-cycle clears it. The controller will only drop the 08 flag when it sees a healthy hall signal again, so the underlying sensor, cable, or controller fault has to be repaired first. After the repair, switching the system off and back on is enough to clear the code.
Is it safe to keep riding with error 08?
No. The motor will cut assist without warning, which is a real hazard in traffic and on climbs. The bike rolls unpowered, but it should be ridden only to a workshop, not on normal journeys.
How much will the repair cost and is it under warranty?
Most repairs land between 20 and 150 EUR depending on whether it is the cable, the controller, or the internal hall sensor. Within the first two years, with proof of purchase and no sign of water or crash damage, the manufacturer usually covers it as a component fault.
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.