Yamaha PW error 71: Battery data communication or voltage fault
The drive unit is not receiving valid data from the battery pack, or it has measured a pack voltage above the 45 V limit. The motor assist, walk assist, and any torque-based support are cut off until the fault clears. The display keeps the code live and the bike will not resume normal operation on its own.
| 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 fees run €40 to €80, a replacement charging plug or lead is €20 to €60, a controller €200 to €450, and a new OEM battery €400 to €900 fitted. |
Likely causes
- Dirty, oxidised, or bent contacts between the battery and the frame cradle
- Battery not fully seated in the mount or lock not engaged
- Damaged charging port, DC plug, or power lead with broken or corroded pins
- Battery management board fault producing an out-of-range voltage signal
- Controller input stage fault on the battery communication line
- Use of a non-OEM or third-party battery that reports an incompatible voltage
How to fix Yamaha PW error 71
- Switch off the system and remove the battery from the frame
- Inspect both the battery base contacts and the cradle contacts for dirt, corrosion, or bent pins
- Clean the contacts with isopropyl alcohol and a lint-free cloth, then refit and lock the battery
- Check the charging port on the frame and the charger DC plug for damage, debris, or bent pins
- Inspect the visible power lead for cuts, kinks, or chafing near the connectors
- Try a known-good compatible charger on a separate socket
- If the code returns, take the bike to a dealer for diagnostic and replacement of the plug, receptacle, lead, controller, or battery as required
Warranty: A genuine component fault on the battery, controller, or wiring inside the two-year warranty period is normally covered; water ingress, crash damage, modified looms, and non-OEM batteries are excluded.
Typical cost: Diagnostic fees run €40 to €80, a replacement charging plug or lead is €20 to €60, a controller €200 to €450, and a new OEM battery €400 to €900 fitted.
Frequently asked
Can I reset Yamaha error 71?
No user reset clears it. The code only goes away once the communication or voltage fault is fixed, usually by cleaning contacts or replacing the failed part at a dealer.
Is it safe to keep riding with this code?
No. Motor assist is cut and riding on a partially diagnosed electrical fault can worsen damage to the battery or controller. Push or transport the bike to the workshop.
How much will the repair cost and is it covered?
A plug or lead replacement is €20 to €60, a controller €200 to €450, and a full battery €400 to €900. A genuine component failure within two years is normally a warranty repair, while water damage or crash damage is 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.