Bosch error 656: Software version error (battery)
Bosch BES2 & BES3Dealer neededRide with caution
The battery's firmware does not match the rest of the system. This appears with new or replacement batteries and after partial updates. A dealer update fixes it.
Likely causes
- New battery with newer firmware than the drive unit
- Drive unit updated but battery not
- Second-hand battery from a different system
- Interrupted update
How to fix Bosch error 656
- Restart the system once
- If you swapped batteries, try the original
- Book a dealer software update with DiagnosticTool
Go to a dealer if: A dealer with DiagnosticTool is always needed to update the battery or drive unit firmware.
Warranty: Normally fixed free after a dealer job; otherwise a small software charge.
Typical cost: Typically 30-60 EUR/USD.
Warranty: Normally fixed free after a dealer job; otherwise a small software charge.
Typical cost: Typically 30-60 EUR/USD.
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 Bosch error 656 myself?
No. Battery firmware can only be updated by the dealer.
Can I keep riding with error 656?
Usually, but with reduced or interrupted assistance and the risk of the system shutting down mid-ride. Ride home carefully or on muscle power alone; do not plan long rides until the cause is found.
Is error 656 covered by warranty?
Normally fixed free after a dealer job; otherwise a small software charge.
Related Bosch codes
Not an official Bosch document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.