pressure switch

Washer would give F21 error code and stop cycle. Would have to unplug, restart with rinse and spin. Some times would not complete rinse and spin, and would have to try a few times in order to get water to drain. Also received a few 5d errors.
Checked drain pump, filter and drain lines. Not much lint in filter, but seemed to work for a few weeks with no problems. I also ran a diagnostic and did not receive any error codes.
The problem keeps occurring on and intermittent basis. We have cut back on the amount of HE detergent per load, not much difference. Today I kept getting 5d errors. Again, checked the drain filter, wiring connections, and eventually the pressure switch.
I checked the switch and found that the pins 4 & 6, the Empty water level setting read zero ohms before I activated and an open, 2M ohms when I activated it. The overflow position, pins 3 & 4 read open in both activated and non-activated positions.
The manual says it should read zero ohms when activated. Is the manual correct, and does that mean I have a bad pressure switch?
Any help would be greatly appreciated, Thanks.