OK, found that bastard and removed him from the Board
Installed a new one... here on the foto the legs are naked, but i did some silicone on them when i installed it (no foto made at this time)
checked it, and everything workes
Testriding, after 1 Km i had a H8 Error again... (while pedaling at 20 km/h )
so i took the motor apart again, to check the Halls... again
oh, and i stripped the alloy-windings on this pedal... so 3 leg puller-Time
... i checked the Sensors again, and they all work fine.. i cleaned it with alcohol and put some silicon on the solderjoints on the backside to protect them (...?)
thats strange, the sensors are working nice, and for the 1 Km i testrided the Bike, it workd like new.
i will put anything back together and try again. dont know what to try next. anyone a idea?