Motor Silicone and Hall Sensor Tools
Use the ONYX Tools post for the tools and materials required when servicing internal motor silicone or replacing hall sensors.
Tools and Parts You’ll Need
For silicone repair:
- Electronic-grade silicone (clear or white)
- Gasket maker
For hall sensor repair:
- Hall sensor (413F / TO-92 package)
QS 205 Motor Silicone Failure
In 2023, a recurring issue was identified in a small batch of QS motors: the original white silicone used to secure internal wiring was replaced with a brittle gray compound. This material degrades over time, breaks apart, and allows internal wiring to shift.
As the compound fails, it can:
- Expose or stress phase and hall wires
- Cause intermittent electrical faults
- Damage or destroy hall sensors
Because motors are sealed, confirming the compound type requires opening the motor.
It is not confirmed whether this issue has been fully resolved in newer production runs.
Symptoms
- Motor bogging, jerking, or vibrating
- Intermittent cutouts during operation
- Motor not running at all
Fix
- Remove as much degraded gray compound as possible
- Inspect all phase and hall wiring
- Resolder damaged connections if hall sensors remain functional
- Replace failed sensors using a 413F (TO-92 package) hall sensor
- Secure wiring using zip ties before reassembly
Hall Sensor Failure Symptoms
Hall sensor faults often overlap with silicone-related issues but are specifically caused by incorrect or missing rotor position signals.
Common symptoms include:
- Motor stuttering or jerking under throttle
- Motor only running when pushed or at higher speed
- Sudden cutouts under load
- Motor not starting from a stop
- Reported hall faults on compatible controllers
Hall Sensor Diagnostics
Confirm hall sensor faults before opening the motor whenever possible.
Quick Troubleshooting
If the motor will not exceed ~10 mph and produces a clicking or stuttering behavior, a hall sensor issue is likely. This is not a definitive diagnosis—confirm using the methods below.
Backup Hall Sensor Connector
- Switch to the backup hall sensor connector inside the bike
- Re-test motor behavior
If the issue persists, the controller or wiring may also be contributing factors.
Visual and System Checks
Use the controller app (AC Aduser) to monitor real-time faults.
- Inspect motor wires near the axle for cuts or exposed sections
- Check rear brake disc for drag against the caliper
- Verify axle nuts are properly torqued
- Inspect the yellow phase wire junction box
- Check controller LED status inside the side panel
- Inspect internal harness wiring for loose or damaged connections
Controller LED Codes
A solid green LED indicates normal operation. A flashing red LED indicates a fault code.
| Flashing | Explanation | Solution |
|---|---|---|
| 1,2 | Over voltage error | Battery voltage is too high for the controller. Check battery volts and configuration. Regeneration over-voltage. |
| 2,4 | Throttle error at power-up | Throttle signal is higher than the preset dead zone. |
| 3,2 | Internal reset | May be caused by some transient fault condition like a temporary over-current, momentarily high or low battery voltage. This can happen during normal operation. |
| 3,4 | Angle sensor error | Speed sensor is damaged or defective.Or feedback signal is erratic. |
| 4, 4 | Hall Galvanometer | Hall galvanometer device is damaged. |
Spin Test (No Throttle)
- Power on the bike
- Elevate the rear wheel off the ground
- Do not apply throttle
- Spin the wheel by hand
Expected result:
- Display registers approximately 1–3 mph
Fault indicators:
- Display remains at 0 mph → likely hall sensor issue
- Motor may run at speed but fail to start from zero
Basic Multimeter Test
- Power the hall sensors (typically 5V supply)
- Connect multimeter ground to hall ground
- Probe each hall signal wire
- Slowly rotate the motor
Expected result:
- Each hall signal toggles between approximately 0V (low) and 5V (high)
- Switching is clean and consistent
Fault indicators:
- No voltage change
- Signal stuck high or low
- Irregular or unstable switching
Method 2: Hall Sensor Tester (Recommended)
- Plug the hall sensor wires into a hall tester
- Power the motor
- Spin the wheel slowly
- The tester should flash LEDs for each hall sensor
- If one LED stays on or off, that sensor is bad
Signs of a Bad Hall Sensor
- Good: Voltage toggles 0V → 5V as the motor spins
- Bad: Stuck at 0V or 5V, no voltage change
- Intermittent: Inconsistent switching, often caused by failing sensors or loose wiring
Hall Sensor Repair
If a faulty sensor is confirmed:
- Open the motor
- Locate the failed hall sensor
- Remove silicone and expose sensor leads
- Desolder the faulty sensor
- Install a replacement 413F (TO-92 package) sensor
- Match orientation exactly (flat side and pin order must match original)
- Resolder connections and verify continuity
- Test sensor output before reassembly
Incorrect orientation will prevent the motor from operating.
If multiple sensors are damaged, replace all three to maintain consistent signal timing.
Silicone Repair Overview
Typical repair workflow:
- Open the motor
- Remove degraded silicone compound
- Inspect phase and hall wiring
- Repair or replace damaged hall sensors
- Secure wiring mechanically (zip ties or equivalent)
- Re-encapsulate using electronic-grade silicone
Use clear or white electronic-grade silicone. Avoid low-quality compounds that harden or crumble under heat.
If hall sensors remain intact, repair may be limited to cleaning, securing, and resoldering connections.
Wire Protector Spacer
The phase wire protector spacer prevents motor wiring from contacting the brake disc during rotation, which would otherwise result in insulation damage, shorting, or complete harness failure.
Important notes:
- The 24 mm silver washer must face the freewheel side
- The spacer installs on the phase-wire exit side of the motor
- Incorrect installation can lead to severe wiring damage or full harness destruction
Motor Wire Protector
ONYX motors include a phase wire protector (commonly referred to as a “motor spacer”) that offsets the wiring exit point away from moving components such as the brake disc and hub interface.
QS motors, including the QS 205, QS 260, and QS 273, use similar spacer systems. The spacers for the QS 260 and QS 273 are currently being redesigned to improve wire clearance and long-term durability.
If damage occurs to the phase, temperature, or hall sensor wiring on QS motors:
- The entire wiring harness can be replaced
- In some cases, individual wires can be repaired, depending on the damage location and severity
Proper installation is critical:
- The 24 mm silver washer installs on the motor side facing the freewheel
- The phase wire protector installs on the side where the wires exit the axle
Failure to follow this orientation exposes the wiring to mechanical contact, increasing the risk of insulation wear, electrical shorting, and motor failure.
Service or Water Damage
If the bike has been submerged above the pedal crank or exposed to pressure washing, water intrusion into the main body can damage electrical components including the controller and hall sensors.
If issues appear after recent service (such as a tire change or motor work), re-check all connections and installation points.
Recommendations
- Inspect for gray silicone proactively if the motor is from a 2023 production batch
- Perform hall sensor signal testing before opening the motor to avoid unnecessary disassembly
- Replace all three hall sensors if more than one shows instability or failure
- Always secure internal wiring mechanically before applying silicone
- Use only electronic-grade silicone (clear or white) for re-encapsulation
- Verify wire routing and clearance before closing the motor
- Confirm correct spacer orientation during reinstallation
- Re-test hall signals and motor startup behavior after any repair work
Consistent inspection and correct reassembly significantly reduce repeat failures related to wiring movement and sensor damage.