Faulty Field Control Hardware.

What does 939 mean?

This fault indicates a problem with the field control hardware. It may only occur during the power-up sequence.

• Component problem with the Field Interface Board.
• Component problem with the Main Control Board.

Click steps to track your progress.

1. 1

   Replace the Field Interface Board.

2. 2

   If the fault is still present after replacing the Field Interface Board, replace the Main Control Board.