Bafang E04 error — cause + fix
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Bafang E04 showing on your ebike display? It means: Motor hall sensor fault. Full diagnosis + fix below.
What Bafang E04 means
Motor hall sensor fault
Most likely cause
Hall sensor cable at motor axle has come loose, corroded, or a sensor inside the hub motor has failed
How to fix it
Disconnect motor cable at axle, inspect for bent pins/corrosion. Clean with contact cleaner, grease, reconnect. If persists, hall sensor inside motor needs replacing (£30-80 depending on motor).
Full diagnostic walkthrough
This error code points at a specific problem. For the complete diagnostic flow with multimeter tests and replacement options, see the dedicated guide:
Which ebikes this code affects
All ebikes using Bafang controllers + hub motors.
Diagnostic tools you'll need
AstroAI digital multimeter
Best for: Verifying voltage-related causes of E04
- Auto-ranging DC
- Continuity beep for connector tests
- ~£15 on Amazon UK
Contact cleaner + dielectric grease kit
Best for: Resolving connector-related E04 errors
- DeoxIT-grade cleaner
- Silicone dielectric grease
Self-amalgamating rescue tape
Best for: Sealing connectors after fixing to prevent recurrence
- Self-bonds, waterproof
- Removable for future service
Clearing the code
Most Bafang codes auto-clear once the underlying fault is resolved. If the code persists after fixing:
- Power off the ebike completely (remove battery).
- Wait 60 seconds (capacitors discharge fully).
- Reinstall battery, power back on.
- Code should be gone if the fault was addressed.
If this code keeps coming back
Intermittent errors usually mean the fault is intermittent too — typically a loose connector, partially broken cable, or a component failing gradually. Don't ignore it; intermittent faults almost always worsen until they become permanent. Work through the related diagnostic flow linked above to find the root cause.