What does error code 30 signal on a Bafang electric unit? A year or so back I bought an electric cargo bike online. The company I bought it from is since then no longer in operation. Since a few weeks every now and then the display shows a wrench symbol and the number 30. At the same time the battery charge indication indicates an empty battery. The bike is still normaly operable. I think this is some sort of error code.
Unfortunately I don't have any manual for the electric components of my bike, so no way to find out myself. I visited a few local bike repair shops, and no-one is familiar with the brand of electric assistance my bike has, and are unable to provide any help.
The label on the electric unit states &quot;Bafang&quot;, which I guess would be a Chinese brand.
Does anyone know what this error 30 could mean?
Here is a picture of the error: 
Doing some more googling I identified this part as the Bafang DP-C07 display unit.
As asked in the comments here is a picture of the motor:
Error 30 suggests a communications problem, a quick google sent me to the manufacturer website with a list of error codes.
Error Codes
I will add more details later if required but for the time being look at the link supplied for more information

It is most likely a simple connection issue.

First unplug and replug all of the connections on your kit including all of the Main Wiring Harness connections (display,
throttle, brake levers) and all of the Motor lead connections with the
Battery and Speed Sensor. Make sure no pins are bent/damaged on any of
the connection plugs and line up the arrows and pins when reconnecting
everything to ensure proper connection.
If Step 1 does not fix the error, check that none of the wiring on your setup is being pinched, especially the cables coming from the
controller. Check to make sure that none of the wiring on your
installation is too taught and is pulling the cables from the
controller.
Open up the controller from the motor core and unplug all of the controller plugs and replug them again ensuring there is no silicone
interference and everything is properly connected.


Info grabbed from above link incase the site goes 404.