The Main PCB does not detect that any (or not enough) water has flowed into the tub based off the pressure sensor frequency.

1.) Is the water supply valve turned on and completely open?
Are the valve screens blocked?
This would also be a good time to test the water pressure supplied to the unit.

Water supply pressure must be between 20 psi and 120 psi (138 – 827). If the water supply pressure is more than 120 psi, a pressure reducing valve must be installed.

2.) Are flood safe hoses being used?
These cannot be used due to the pulsing operation of the water valves.
Only the standard supplied hoses should be used.

3.) Unplug the unit.
Check the harness connections at the water valves and at the Main PCB.

4.) Disconnect the harness connections from the water valves. Test the resistance of each valve. Resistance should be approximately 800-1200Ω, for 120volt AC valves and 26-28Ω  for DC valves *If an open is read, replace the valve.*

5.) Plug in the unit and activate test mode to cycle through all water valves.

Voltage should read 120Vac, (Or 12v for DC models).
If no voltage is read, check voltage at the Main PCB.
If no voltage is present at the Main PCB, replace the Main PCB.
If voltage is present, suspect a wiring harness issue.

6.) If the valves are working in test mode, does the water level frequency decrease as water comes into the tub?

If not, inspect the pressure sensor hose and air chamber for a crack or blockage. Pin 1 to Pin 3 should read 20 to 25 ohms. With the pressure sensor connected, measure voltage from Pin 2 to Pin 3 and Pin 2 to Pin 1. Both should read 2.5-3Vdc. For greater detail on how to check the pressure sensor please see the “PE” Error code article.