Whirlpool Dishwasher ADG7340

Gents

I have the above dishwasher with a serial code of 8542 340 15810

We are having a problem that the unit will go through its wash cycle on any of the 3 washes then it starts beeping constantly with the right hand on LED flashing four times.

Some times it has heated the water and is drying other times it doesn’t seem to heat the water and starts beeping, there is no apparent consistency. It always shows 4 flashes which i presume is an error code?

I have been looking at the forum and seen similar faults on other whirlpool models.

I have taken the front cover off so i can see inside the machine and there is no sign of leakage in the drip tray.

I am an electrical engineer (in engineering not white goods!!) and have checked the easily accessible connection all look ok, i have run the machine with the covers off and it has gone thru the wash cycle gone into the drying cycle and started beeping, when i have opened the door all the water has drained away and the machine is hot as if drying mode.

Any ideas where i should look.

Cheers
Haydn