Ride1Up's own error codes
These codes come from Ride1Up's official sources, listed at the bottom of the page. Check the rider age in your manual. If your screen shows a code that isn't on this list, your bike may use a different display: find your display .
Quick answer
Error 12 on the Ride1Up Roadster V2 / CF Racer1 means “Failure of the current sensor.” Most likely cause: an internal controller fault. Try this first: turn it off and on again.
Code meanings vary by brand. The same number can mean different things on different displays and controllers. Check your bike's manual to confirm.
About the Ride1Up Roadster V2 / CF Racer1
Ride1Up's Roadster V2 and CF Racer1 error code pages show this same table. source Ride1Up's manuals page links an SW102 display manual for the Roadster V2. That manual lists a few more codes (04, 05, 13, 22). source
In plain English
The controller has a circuit that measures current, and this code means that circuit has a fault. It's an internal problem, so there's little to do yourself beyond ruling out loose connections and water.
Step-by-step checklist
Reset
Work from the top. Steps go from free and easy to shop jobs. Switch the bike off before touching any connector. Tick each step as you go. Your progress is saved on this device.
As an Amazon Associate I earn from qualifying purchases. Steps marked "affiliate link" link to Amazon.
1 Turn it off and on again Free Switch the display off, wait 30 seconds, then switch it back on. If the code clears, note what you were doing when it appeared, in case it comes back.
2 Unplug and check the main connectors Easy Switch off and remove the battery. Find the round waterproof plugs along the cables (usually near the handlebar, down the frame and near the motor). Pull each one apart, look for bent pins, water, green corrosion or melted plastic. Melted or burnt plastic means stop and see a shop. Clean green corrosion with electrical contact cleaner and let it dry fully, then push the plug back together with the arrows lined up.
Need it? Electrical contact cleaner spray on Amazon (affiliate link)
3 Dry the bike out if it got wet Moderate If the problem started after rain or washing, remove the battery and leave the bike somewhere warm and dry for 24 to 48 hours, then test again. Don't use a heat gun or put the bike next to a heater.
4 Ask a Bafang dealer to read the fault Shop job Bafang dealers have a diagnostic tool that reads detailed fault data and can update firmware. It often pins down internal faults quickly.
5 Have the controller tested Shop job If the wiring checks out, the controller may be faulty. A shop can test it and replace it if needed.
⚠ When to stop and get a shop
Stop and see a shop if the controller is hot to the touch, smells burnt, or has melted plastic on any connector. Don't open the controller or cut into the main wiring harness.
Anything inside the battery, the controller, or the thick high-power motor wires is a job for a qualified e-bike shop.
Parts you might need
As an Amazon Associate I earn from qualifying purchases. These links go straight to Amazon.
Only buy a part if the free steps didn't fix it. Always match the voltage and connector type to your bike.
Electrical contact cleaner spray Cleans dirt and corrosion from connector pins and battery contacts.
View on Amazon
Still not fixed?
Pages to try next:
When it's time for a shop: if you've worked through every step and the problem is still there, take the bike to an e-bike shop. Bring your notes on when it happens, plus the code.
Words on this page: Controller
Sources
Written and checked by Kazolt against the sources above. Last checked: October 23, 2026. How we write our fixes
Does Error 12 mean something different on your bike? Let us know so we can fix this page.