Bosch error 506: Internal fault in the drive unit
An internal drive unit fault in the same family as 500 and 505. Assistance may stop or become erratic. A single occurrence after a restart is not alarming; repeated occurrences mean the motor needs to be checked.
Likely causes
- Internal electronics or sensor fault
- Water ingress into the drive unit
- Damage from overheating or a tuning device
- Mechanical damage inside the gearbox affecting sensors
- Outdated firmware with a known bug
How to fix Bosch error 506
- Full power cycle: switch off, remove the battery, refit, switch on
- Let the bike dry if it has been wet
- Short test ride; note the conditions under which the code returns
- If repeating, stop riding with assistance and see a dealer for a DiagnosticTool read-out
Warranty: Bosch drive units, batteries and displays carry a 2-year manufacturer warranty in most markets; a genuine internal fault within that period is normally replaced free through the dealer.
Typical cost: Drive unit exchange 500-1000 EUR/USD out of warranty; independent repair often 200-400 EUR/USD.
Frequently asked
Can I reset Bosch error 506 myself?
Only a restart. A persistent 506 has to be diagnosed and repaired at a dealer.
Can I keep riding with error 506?
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 506 covered by warranty?
Bosch drive units, batteries and displays carry a 2-year manufacturer warranty in most markets; a genuine internal fault within that period is normally replaced free through the dealer.
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.