Cause of error code E44

Boiler is powered by three wires, hot, neutral and ground. E44 displays when neutral wire isnot neutral.

Solution for error code E44

1. Measure incoming power with volt meter. Is terminal 120 VAC (L) approximately 120 VAC? Is 120 VAC (N) approximately 0 VAC?
Yes: -> 2 
No: Correct power supply to boiler.

2. Verify order of pins on J2. Pin order should be: empty, black (or red), white, green. Measure volt on pins of black wire and white wire. Is wiring/pins in right order? Does black/wire have 120 VAC? Does white wire/pin have 0 Vac? 
Yes:Replace control module. 
No: Replace wire Harness.