Code 21 on Display

[Chartmaster]

So, After a brief 9 mile ride, my 2 day old Rad Rover 6+ decided to have an error 21 code on the display. I went through the on-line support and did all the checks suggested on the site, but had no luck in restoring the bike into a workable state.

I did contact support subsequently and they ordered a new controller for my Bike under warranty, which is expected and the service was really prompt.

So now waiting for the controller (it has not been shipped as we speak) i was hoping some folks may have insights on what will cause the error and if there is a fix which does not involve replacing the controller, i.e. can it be reset in some way to clear the error or is the controller a throw away part. Obviously having had the bike for 2 days and only had one ride on it i am quite disappointed. I truly hope this is a once-off occurrence.


Any insights would be appreciated...

[Chartmaster]

Update on the Control Unit. I did receive the new one over the weekend and installed it, which in itself was not easy as you need hands the size of a toddler's and be able to see around corners. But it's in and the bike is now working as intended.
Now with the faulty Controller, i would like to see if it can be fixed. Has anyone attempted this with success ?

[JedidiahStolzfus]

What I've noticed with the innovation of these bikes is that the designers never heard of the term "stress relief".  Wires down there at the controller should not be bent as sharply as they are.  There's a good possibility something has snapped inside one of those cables throwing the Error 21. 

To troubleshoot it that condition, you'd have to open the control module, and then do a continuity test between all the connections on the board inside and the connectors on the outside.  Fixing it would be just a matter of replacing that cable, which will probably involve some desoldering and "re" soldering.
I think most of those cable pigtails can be purchased on Amason.
It's also possible that a solder joint on the board cracked due to them getting these things from China and that they use leadfree solder.  Leadfree solder is more brittle and takes more skill to solder, and the slave labor they use over there does really crappy solder work.  Good solder is far more forgiving with high speed soldering, than lead free.

You can open the controller and look for bad solder joints.  Try moving poking at them with a dental pick, see if they move at all.  I'd say look for cold joints, by looking at the ones that are dark and not reflective, but it's probably lead free so finding them that way is far more difficult.
If you're unsure if a joint is good or bad, just reflow it with a hot soldering iron.  You can flow good solder in with the bad solder and it'll work fine.