Cause of error code E51

Supply temperature sensor is open. No continuity.

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 white wires between control board and sensor. Continuity? 
Yes: -> 3
No: -> Replace wires 

3. Unplug J5 connector on control board. Using digital meter measure resistance between terminals J5-11 and J5-3. Estimate sensor temperature. Does it fall in the range of the resistance chart? 
Yes: Replace control module
No: Replace supply water sensor.