Pulsator
How old is your Bosch? Modern ones have the following problem.
Here in the UK, there is a common fault with Bosch and Siemens dishwashers: that of the blocked 'fill tube'. This tube allows water to enter the tub via the sump.
This is a corrugated tube that comes down from the heat exchanger/fill matrix on the left-hand side, and enters the sump wall, tangentially, at the sump's front wall. It has a habit of clogging up with grease and food deposits.
To clean this tube, isolate the machine from the mains electricity supply. Remove the lower basket. Remove the filters.
Carefully leaning into the machine, with a battery torch (flashlight), you may be able to see a small hole about the width of a finger, set into the vertical sump wall at the 6 O'Clock position. This needs to be GENTLY rodded out, using slim bottle-brushes.
DO NOT use excessive force, as the tube could come adrift, or be punctured.
The tube leads off left, upwards and backwards, and terminates at the water level pressure vessel. Even a small amount of crud can cause weird water level problems.