hi i've had a bh evo cross for 2 years and the motor has just died, i can't believe it, a 2 grand bike, that was regularly serviced and the motor packs up, anyone else had that problem , i have to say trying to tried it without power, difficult !!,
I'm assuming this is a rear hub motor?
Put the bike on a stand. Turn off the power. Try to turn the motor wheel, if it will not turn or is very difficult to turn, disconnect the motor from the controller. There should be a plug somewhere near the motor. Try to turn the motor again. If it turns (forwards should be free, backwards will have a slight resistance) then the controller is faulty.
The bike although rear hub utilises a TS BB so issue may be the TS system.
OP is correct though ,it is under warranty so the dealer should sort out the issue.