Carrera problem

[L6mbt]

My Carrera E-Vengeance, which has served me well for three years, has now gone sulky! It was fine a few days ago; I removed the battery for a charge but, although the battery now shows a full charge, the bike does not respond, although all the operational lights come on. (It is a 2018 model with the Bafang motor so I had hoped it would not suffer with the common Suntour problems). I occasionally get a momentary surge on startup, so there is a flicker of life in the system. I have looked in vain for damaged or loose wires; I thought the pins which connect the battery to the electrical circuit could be a suspect point so cleaned those thoroughly, but without success. Any ideas, please?

 

[Nealh]

Check the motor connector hasn't been disturbed.
Disconnect any brake sensors to rule out a faulty one.
If still no luck one will have to wire test the controller mosfets for resistance and check the motor Halls are good.