Bosch error 655: Multiple battery errors
The battery management system has logged several faults at once. Bosch's advice is to restart and see a dealer if it recurs. It usually means the pack is in poor health or has suffered a serious event such as deep discharge, impact or water.
Likely causes
- Battery deeply discharged and left flat for months
- Several weak cell groups
- Water damage inside the pack
- Impact damage
- BMS electronics failure
How to fix Bosch error 655
- Switch off and remove the battery
- Clean the contacts and charge fully on the original charger
- Refit and restart
- If the code returns, stop using the battery and have a dealer read the BMS with DiagnosticTool; a damaged lithium pack is a safety risk
Warranty: Bosch batteries carry a 2-year warranty (or 500 full charge cycles, whichever comes first); deep discharge from long storage is often classed as user damage.
Typical cost: Almost always ends in a battery replacement at 500-900 EUR/USD out of warranty.
Frequently asked
Can I reset Bosch error 655 myself?
Only by restarting once. If it comes back, the battery must be assessed; do not try to reset it repeatedly.
Can I keep riding with error 655?
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 655 covered by warranty?
Bosch batteries carry a 2-year warranty (or 500 full charge cycles, whichever comes first); deep discharge from long storage is often classed as user damage.
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.