Triple check connectors and every inch of every wire. Blow out each connector and reconnect.
Its nice to have a spare controller that is SENSORLESS like from Greentime EVFitting on Aliexpress.
Its also nice to have a spare throttle.
Disconnect the pedal assist and try to see if it works.
https://electricbike.com/forum/forum/kits/bafang-mid-drives/14346-bbshd-error-code-12-please-help
- I get error code 12 and bafang non-functioning. Shutting off and restarting consistently clears code and then runs smooth for miles.
- From C961 Manual error code 12 is "current sensor abnormality", which I believe is correct for code (old BBS manual I have says code 12 is "Temperature inside of battery is
un-normal") (Random red herring or possible important detail, at 600 miles it started randomly adding resistance when not assisting (if you leave on come to stop and move bike backward/moving peddles it feals like brakes slightly on, no code shown, shutting off and restarting behaved normally immediatly, then this stopped for 50 miles and happened twice this week.)
- I noticed that one of the leads from the brakes was disconnected. Didn't notice as don't really need the cutoff as stop pedaling before braking usually . Connected and never got error again.
- Now that I have the controller separated from the motor body and I have plugged all the wires back in, when I turn the power on the throttle seems to be working but there is still an error code number 12 on the display.
- I confirmed I was correct. it's a shunt sensor error. It might be fixable but you'll likley get intermittent errors. New controller is the sure fix for error 12.
...from same website