Bosch error 591: Authentication error
A component (most often the battery) failed the system's authenticity check. The drive unit refuses to work with it until it has been authenticated by a dealer. This shows up with replacement batteries, some third-party batteries, and occasionally after a firmware hiccup.
Likely causes
- A replacement or second battery that has never been paired to this drive unit
- Third-party or rebuilt battery without valid Bosch authentication
- Battery contacts dirty so the authentication handshake fails
- Interrupted start-up during the handshake
- Firmware fault in the battery or drive unit
How to fix Bosch error 591
- Switch off, clean the battery contacts, refit and restart
- Try the original battery if you have more than one; if that works, the other battery needs pairing
- Restart a second time after a full power cycle with the battery removed
- If the code persists, a dealer must authenticate the battery with DiagnosticTool; non-genuine batteries cannot be authenticated
Warranty: Using a non-Bosch battery voids the drive unit warranty; a genuine battery that fails authentication is handled under warranty.
Typical cost: Free to a small charge for dealer pairing of a genuine battery; a genuine Bosch battery is 500-900 EUR/USD if you have to replace a third-party one.
Frequently asked
Can I reset Bosch error 591 myself?
No, apart from cleaning contacts and restarting. Authentication itself is a dealer operation.
Can I keep riding with error 591?
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 591 covered by warranty?
Using a non-Bosch battery voids the drive unit warranty; a genuine battery that fails authentication is handled under warranty.
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.