Bike Won't Turn On/Error Code 12

[Pabigbear]

I have an M2S All Terrain Ultra HT bike with the Bafang M620. A few weeks ago I rode the bike for a few miles on a wet, grassy road while it was raining hard. Then parked it under my covered porch when I got home. The next day I had it in the bed of my truck while it drizzled all day. The following day after a few miles it threw Error Code 12 on the display, "Fault with current sensor inside controller". Tech support said it was likely caused from moisture issues and after drying out would be fine. Several days parked beside my woodstove and no luck. It would work one day for a few miles, then throw the code. It did this for several days. Since it was a muddy mess I knew I needed to wash it before diving into the issue further. I washed it with a garden hose and now it will not turn on at all. The status lights on top of the battery do not light up with a charged battery. I pulled the battery and checked the 45amp fuse on top and it's good. I did notice after it wouldn't turn on when rolling the bike backwards there is considerable resistance in the motor area. I do not recall it being like that prior to washing it and not turning on. Tech support is telling me to replace the controller because it's drawing current when it shouldn't. Does this make sense? I do not want to drop $125 throwing parts at it if it's not likely this is the problem. Thanks for any input.

 

[Gionnirocket]

I'd drop the motor and remove the controller to one check for obvious signs of failure and two to let it dry out better.
You'll at the very least want to change the gasket at this point.
Same time go over all connections from the motor out...
You could try replacing the display if you have a spare.

Is your motor UART or CANbus?

 

[PedalUma]

I'll bet there is some rust in there too. It is not a dive watch, it is only water resistant. As it expands and contracts with temp changes, that can draw in vapor which condenses. Every bike I have seen with trouble rolling backwards has had internal rust. The worst are people who use there bikes at horse shows and then leave them in their horse trailers between shows. That 5hit is corrosive. I hope it works out; maybe just opening it letting it dry and then fresh grease with the new gasket will do the trick.