Yamaha PW error 37: Torque sensor voltage abnormality during riding
The motor controller has detected that the torque sensor's output voltage is outside the expected range while you are pedalling. As a result the drive unit cuts motor assist and the bike behaves like an unpowered bicycle until the fault is cleared. The walk-assist function is also disabled while the code is active.
| Drive system | Yamaha PW series (PW-X3, PW-S2, PW-ST, PWseries CE - also Giant SyncDrive) |
| Severity | Dealer needed |
| Keep riding? | Do not keep riding |
| Typical cost | Diagnostic and reference voltage adjustment typically runs €60–€120, a torque sensor replacement €150–€300, and a controller assembly €300–€550 depending on the PW model. |
Likely causes
- Moisture or water ingress into the torque sensor or its connector
- Loose or partially seated connector at the torque sensor or controller
- Corroded or damaged wiring between the torque sensor and the controller
- Internal torque sensor failure (strain gauge drift or signal error)
- Controller input circuit fault misreading the sensor signal
How to fix Yamaha PW error 37
- Stop pedalling and switch the system off at the display.
- Remove the battery and inspect the bottom bracket and motor cradle for water, mud, or impact damage.
- Unplug and reseat the torque sensor connector, then dry any dampness with compressed air or a clean cloth.
- Refit the battery, switch the system on, and check whether the code clears.
- If the fault returns on the next ride, do not continue using motor assist.
- Book the bike in with an authorised Yamaha or Giant dealer for torque sensor reference voltage adjustment, sensor replacement, or controller replacement as required.
Warranty: A genuine torque sensor or controller failure inside the standard two-year warranty period is normally covered, while water ingress, crash damage, and wear-related issues are usually excluded.
Typical cost: Diagnostic and reference voltage adjustment typically runs €60–€120, a torque sensor replacement €150–€300, and a controller assembly €300–€550 depending on the PW model.
Frequently asked
Can I reset yamaha error 37?
A power cycle may clear the fault temporarily, but the code will usually return on the next ride because the controller has logged a real sensor voltage problem. A permanent reset can only be performed by a dealer using the Yamaha diagnostic tool.
Is it safe to keep riding with error 37?
No. Motor assist is cut and the torque sensor signal is unreliable, so continuing to pedal under power can stress the controller and motor. Ride unassisted to a safe place and arrange transport to a dealer.
How much will the repair cost, and is it covered by warranty?
Expect €60–€550 depending on whether the sensor needs adjustment, replacement, or the controller has to be swapped. If the failure is a genuine component defect inside the two-year warranty window, Yamaha or Giant normally covers it; water damage and crash damage are excluded.
Related Yamaha PW codes
Manuals and video
Official source: cdn2.yamaha-motor.eu
Not an official Yamaha PW document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.