Brose error 74: Internal data error detected
The drive system has detected an inconsistency in the data shared between the motor, battery, and display. This is a self-diagnostic message rather than a single failed part, so the controller disables motor assistance as a precaution and the bike behaves like an unpowered bicycle until the fault clears. Speed and cadence readings may also drop to zero. You can still pedal home, but without assist.
| Drive system | Brose Drive (S, T, C - also used by Bulls, Rotwild, Fantic, BH, Trek Allant) |
| Severity | Dealer needed |
| Keep riding? | Ride with caution |
| Typical cost | Dealer diagnostics usually run 50 to 100 EUR, harness or connector repairs 80 to 150 EUR, and a replacement display or motor control unit 250 to 500 EUR fitted. |
Likely causes
- Loose or corroded connectors between the motor, battery, and display harness
- Moisture ingress in a motor or display connector after washing or rain
- Firmware mismatch between components after a partial update
- CAN-bus wiring damage from a crash, impact, or a kinked cable
- Internal fault in the display, motor control board, or battery BMS
How to fix Brose error 74
- Switch off the system completely using the control panel button.
- Wait at least 30 seconds, then switch the system back on and check whether the error clears.
- Inspect visible wiring at the motor, battery, and display for looseness, kinks, or corrosion.
- Unplug and reconnect the main harness plugs to clear any poor contact, then power up again.
- If the bike has been washed or ridden in heavy rain, let it dry fully indoors before retesting.
- Take it to a dealer for a diagnostic read-out and firmware check if the error returns after one or two resets.
Warranty: A genuine internal component failure inside the two-year frame is normally covered under warranty, while water ingress, crash damage, and corroded connectors from poor maintenance are typically excluded.
Typical cost: Dealer diagnostics usually run 50 to 100 EUR, harness or connector repairs 80 to 150 EUR, and a replacement display or motor control unit 250 to 500 EUR fitted.
Frequently asked
Can I reset brose error 74?
Yes, switch the system off at the control panel, wait at least 30 seconds, then switch it back on. If the message reappears within a few minutes the fault is still active and a dealer diagnostic is the next step.
Is it safe to keep riding with this error?
You can pedal the bike home without assist, but motor support will stay off until the error clears. Avoid steep climbs or heavy loads, as the added strain on you and the drivetrain is unnecessary.
How much will the repair cost and is it under warranty?
Expect 50 to 100 EUR for a dealer diagnostic, with a straightforward wiring fix around 80 to 150 EUR and a control unit replacement 250 to 500 EUR. If the failing part is a confirmed manufacturing fault within two years, Brose and the bike brand normally cover it.
Related Brose codes
Manuals and video
Official source: Brose error code table, Pedego dealer service guide
Not an official Brose document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.