Cause of error code E51

Supply Sens Open.

Solution for error code E51

1. Is harness plugged into Supply Water Sensor? Is harness plugged into Control Module J5?
Yes: -> 2.
No: Insert harness.

2. Disconnect J5 from Control Module. Using digital meter measure check continuity of brown wires between Control and Sensor. Continuity?
Yes: -> 3.
No: Replace wires.

3. Using digital meter measure resistance between Supply Water Sensor terminals J5-11 and J5-3. Measure resistance of Sensor with digital meter. Estimate Sensor temperature.
Yes: Replace Control Module. 
No: Replace Supply Water Sensor.