water indicator on a whirlpool dishwasher

Hi,
I’ve had a Whirlpool ADP 4501/5 dishwasher for 2 1/2 years and along with lots of other people it seems, have a fault whereby the cycle nearly completes but then stops and intermittently flashes four times. I know that’s something to do with the drainage and another similar post had a reply saying that’s the water indicator which needs cleaning with hot water and a toothbrush!
Can I just check that the water indicator is the black grid thing which you see if you peer around the corner after removing the filters? It was pretty white and fatty.
Will be s*d’s law if that’s the problem after taking the thing apart and altering the level of the intake pipes etc.