It means that a fault has been detetected. It doesn't give any clues as to what the fault is. For that you have to go to dealer that has the Impulse 1.0 software to interrogate the system.
You can check all the connections, which probably means removing the motor, which is fairly straight forward. After that, you have to open the motor to see if water has got in and damaged something.
These people can do some repairs to the motor, otherwise you have to get an exchange one from Germany.
Spare parts, bearings and repair service for most common ebike motors
www.performancelinebearings.com