Yamaha PW error 38: Crank sensor voltage fault at standstill
The drive unit has detected an abnormal voltage on the crank (torque) sensor's U or W phase while the motor is not running. Because the sensor reading is outside the expected range, the controller cuts motor assist and disables walk assist as a protective measure. The display continues to power on but the bike behaves like an unpowered bicycle until the fault clears.
| 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 | Expect a dealer diagnostic at €40-80, torque sensor replacement €120-220, controller €180-320, and a full drive axle assembly €350-550 including labour at an authorised Yamaha service point. |
Likely causes
- Loose or corroded connector at the torque sensor near the bottom bracket
- Moisture ingress into the torque sensor housing after washing or wet riding
- Damaged internal wiring inside the crank or drive axle assembly
- Worn or failed torque sensor PCB
- Controller reporting an incorrect phase voltage reference
- Crash or impact damage distorting the sensor mount
How to fix Yamaha PW error 38
- 1. Switch off the display unit using the power button.
- 2. Switch off the battery at the isolator or remove the key, wait 30 seconds, then power the system back on.
- 3. Ride briefly on a quiet road and check whether the code reappears under pedalling.
- 4. Remove the battery and inspect the torque sensor connector at the bottom bracket for moisture, corrosion or a pushed-out pin; clean and reseat if accessible.
- 5. Check the crank bolts and axle area for visible damage or water staining.
- 6. Reconnect everything firmly, refit the battery and run a short test ride.
- 7. If the code returns at standstill or while riding, stop using the bike and book it in with an authorised Yamaha dealer for torque sensor, controller or drive axle replacement.
Warranty: A genuine component fault of the torque sensor, controller or drive axle inside the standard two-year Yamaha warranty is normally covered, while water ingress, crash damage and wear-related failures are treated as owner responsibility.
Typical cost: Expect a dealer diagnostic at €40-80, torque sensor replacement €120-220, controller €180-320, and a full drive axle assembly €350-550 including labour at an authorised Yamaha service point.
Frequently asked
Can I reset Yamaha error 38?
Yes, switch the display off, switch the battery off, wait about 30 seconds, then power the system back on. If the code clears and does not return during a short test ride, normal operation resumes. If it comes back, a dealer must diagnose the torque sensor, controller or drive axle.
Is it safe to keep riding with Yamaha error 38?
No, motor assist and walk mode are disabled as a protective measure and the fault points to a sensor or controller problem that should not be ridden under load. Pedalling unpowered to reach a safe location or a dealer is acceptable, but the bike should not be used in traffic until the fault is cleared.
How much does it cost to fix Yamaha error 38 and is it under warranty?
Repairs range from about €120 for a torque sensor to €350-550 for a drive axle assembly, plus a €40-80 diagnostic. A genuine internal component failure within the two-year Yamaha warranty is normally covered, but water ingress, crash damage and worn parts are not.
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.