Whirlpool ADG 7470/1 F8 error?

Hi all,

Our integrated dishwasher (above) will not empty. It’s less than 2 years old but with a family of 5 it gets used almost every day.

Have checked waste water pipe but no blockage. Inside have cleaned filters and checked as best as I can (waste water removed manually) but no blockage detected in the sump. Have reset as per instructions on this forum and also unplugged for 24 hours and restarted. Same problem occurs in that it works up until it needs to drain then fails. Waste water can be sucked through the waste hose manually so fairly sure no blockage.

On resetting and opening the door, the light on the right hand button (restart button?) flashes 8 times. Then a break, then a further 8 flashes etc.

Reading here it seems like it could be a blocked pressure switch and a search on YouTube suggests maybe the same:

https://www.youtube.com/watch?v=RfeFTdSdNYQ

I have a basic level of skills as you guys will see from my other posts (thanks to your help!). Have changed washing machine pumps and FF thermistors before now so would like to see if this pressure switch is blocked before I call an engineer. Only problem is I don’t know where to find it or how to get to it to see if it is blocked.

If I’m on the right track please could you point me in the right directions of this pressure switch so I can take a look?

Thanks
Doug