Inspect the filter screen where the supply line connects. Remove any debris or deposits that may have built up using a toothbrush or warm running water. If you cannot clear the clog, it will be necessary to replace the valve (the filter is not removable on most inlet valves).
Test the water inlet valve for continuity using
First, inspect the coil for an indication of it's ohm rating.
If no information is printed on the coil, then use the range of
170 to 500 ohms. Set the multitester to the ohms setting X100
(if available, otherwise use the nearest ohm setting). Place a
probe on each terminal. The multitester should display a reading
that matches the coil's rating or if you don't know the rating
then it should fall into the range of 170 to 500 ohms. If the
water inlet valve does not pass this test, it should be replaced.
If the inlet valve has two coils, test the second coil in the
same way (note that they may not have the same ohm rating).
The valve can also fail mechanically. So even
if it passes the electrical test, it may still require replacement.
If you have ruled out all other possibilities, go ahead and replace