Yamaha PW error E4: Motor / drive unit fault
Yamaha PW series (PW-X3, PW-X2, PW-X, PW-ST, PW-TE, PW-SE, PW-CE) and Giant/Liv SyncDriveDealer neededRide with caution
E4 reports a motor-side fault: the drive unit detected abnormal motor behaviour such as a phase or hall sensor error. The motor may hum, stutter or not assist at all. On some model years E4 is also shown when the crank rotation cannot be detected. Also shown on Giant/Liv (SyncDrive) bikes, sometimes with a leading zero (E01) or as 'Er' followed by the number on older Yamaha displays.
Likely causes
- Motor phase or hall sensor fault
- Internal wiring inside the drive unit
- Water ingress
- Foreign object jamming the drive
How to fix Yamaha PW error E4
- Switch off and check nothing is jammed in the chainring or crank area
- Power-cycle
- Check the drive unit for water or damage
- Book a dealer diagnostic if E4 returns
Go to a dealer if: Dealer with the Yamaha/Giant diagnostic tool (Yamaha PW diagnostic or Giant's RideControl/e-bike diagnostic software) is needed to read the fault log and test the component when the home checks do not clear the code.
Warranty: Component faults inside the drive unit, battery or display are covered by the bike brand's warranty via the dealer; damage from crashes, water ingress or tuning devices is not.
Typical cost: Out of warranty this is usually a drive unit repair or exchange, which is costly.
Warranty: Component faults inside the drive unit, battery or display are covered by the bike brand's warranty via the dealer; damage from crashes, water ingress or tuning devices is not.
Typical cost: Out of warranty this is usually a drive unit repair or exchange, which is costly.
Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.
Frequently asked
Can I reset E4 myself?
Only a power-cycle.
Can I keep riding with E4?
Pedal without assist only; do not keep forcing a motor that stutters.
Is E4 covered by warranty?
Yes within the warranty period for an internal fault.
Related Yamaha PW codes
Not an official Yamaha PW document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.