whirlpool dishwasher ADP4652

Hi Guys I’m looking at a Whirlpool ADP 4652 with an intermittent fill problem.when it doesn’t fill properly it just surges where the motor is running out of water when it energises.There is no fault code operating the customer just switches m/c off coz of the surging noise.I took the breather off flushed it through checked the paddle wheel & red switch all fine.I didn’t know about the pressure switch in the sump so I will check that next time.Of course after I cleaned it the m/c behaved itself.I just wondered apart from the sump switch is there anything else I should look at when I go back.Thanks Mack.