Hi.. the intake / drain light is flashing and or solid and the dishwasher isn't working.

I've checked the impellor at the non-return valve. its clear and it turns.
I haven't checked the other impellor with an improvised fork tool, but the access seems alot smaller on this model than the incognito model.
I've checked and cleared the filter at the water supply valve. it was blocked with some white material.. plastic ? the water heater was changed a couple months ago so maybe somehow from there. But unfortunately a restart.. results in the same intake/ drain light flashing, with no f code.

I believe the water valve is working as it seems to vibrate.
Is there a secret to resetting ?
What is the process of a dishwasher .. ie.. Empty of the water inside.. add water ..
Is it possible the drain pump is clogged.. can i test it without opening the dishwasher? ie.. add water to the tub.. see if it drains?

Thanks

----- update -----
I decided to switch out the intake valve with a generic one and save about $400. Thanks to Scott the Fix it guy's video .