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Rad Power Bikes error 04: Throttle not in home position
Rad Power Bikes with Bafang hub motor and Rad LCD display (RadRover, RadCity, RadWagon, RadRunner, RadMini)Fix at homeRide with caution
The Rad display uses the Bafang UART error list, and 04 means the throttle read above idle at power-up. The bike switches on but gives no assist until the throttle reads its rest position. Common after rain or a bumped half-twist throttle.
Likely causes
- Throttle twisted or bumped while switching on
- Half-twist throttle sticking and not springing back
- Water in the throttle connector on the handlebar harness
- Throttle hall sensor or wire damaged
How to fix Rad Power Bikes error 04
- Switch off, let the throttle rest, switch on again
- Check the throttle rotates freely and returns; clean grit from under the grip
- Unplug the throttle at the handlebar connector: if the error clears, replace the throttle
- Dry and clean the connector; add dielectric grease
- If 04 persists with the throttle unplugged, contact Rad support about the controller
Go to a dealer if: Go to a shop or Rad support if a new throttle does not clear the code.
Warranty: Rad Power Bikes gives a 1-year limited warranty on electrical parts (2 years on some newer models and regions); contact Rad support with a video of the error before buying parts.
Typical cost: Rad throttle about USD 30-45; a controller around USD 100-150.
Warranty: Rad Power Bikes gives a 1-year limited warranty on electrical parts (2 years on some newer models and regions); contact Rad support with a video of the error before buying parts.
Typical cost: Rad throttle about USD 30-45; a controller around USD 100-150.
Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.
Frequently asked
How do I reset Rad error 04?
Power cycle without touching the throttle.
Can I keep riding?
Yes as a regular bike; pedal assist usually returns once the throttle is unplugged.
Warranty?
Throttles that fail early are covered; water damage may be refused.
Related Rad Power Bikes codes
Not an official Rad Power Bikes document. Compiled from workshop experience and public service information; details can differ per system version and bike brand.