When starting the dishwasher there is only a hum but nothing else happens

The first thing a Bosch dishwasher does when you start a program is run the waste pump. This ensures that any residual water and waste is removed from the machine before the wash program begins.

The hum you can hear is most likely the pump motor trying to drive the impeller. This can become clogged with waste and seize up, preventing the wash cycle from starting. There is an easy way to check this:

(It's easier to do this with the washer empty)

1: Select a wash program

2. Press "Start" and wait for the humming noise

3. Open the door and pull the bottom basket forward or lift it out completely

4. Find and lift the float (the plastic dome/mushroom in the bottom of the washer) all the way up

5. Keep the float lifted and the dishwasher should pump out. Stop if/when you hear a gurgling noise as this means it's empty and pumping mostly air.

6. If the pump doesn't start, lift the float again for about 1-2 seconds then let it drop again for 1-2 seconds. Repeat this 10-20 times and see if the pump starts. The repeated stop/start signals to the pump motor can sometimes free a seized impeller.

If the pump does start, keep lifting and dropping the float switch (1-2 seconds each time) to see if the pump starts every time. If it does, you should be OK to use the washer, but further action is needed to stop the problem returning.

When you've done all this, post the results here and I'll advise you what to do to fix the problem or prevent it from returning.