My bosch dishwasher won't start

https://bosch-dishwasher-errors.com/bosch-dishwasher-error-code-e01/

Reset the dishwasher by pressing and holding the "Start" button for at least three seconds. Depending upon the Bosch dishwasher model you have, you also can push the "Cancel-Reset" button to reset the dishwasher. Select a new cycle and press "Start."

Here is an excerpt from "Bosch Dishwasher Troublesoooting".

Running a Test Cycle
Bosch dishwashers have a test cycle which can be run as a troubleshooting measure. The method to run this test cycle is similar across the Bosch dishwasher range so if your dishwasher features seems different from those described below then try experimenting, as the process is fairly straight forward and will be very similar. Bosch dishwasher model numbers are usually found around the top or lip of the door. One of the most common differences between dishwasher models is simply the names of the buttons. For example in the first example below, POWER SCRUB PLUS and REGULAR WASH may be called WASH and ECO depending on your dishwasher model and the country you are in. The other key difference is whether your dishwasher has a display panel (which can display error codes) or not (in which case a program light will illuminate to tell you the fault.
To run the test cycle hold down the POWER SCRUB PLUS and REGULAR WASH buttons. Whilst held down press the ON/OFF button. The lights above them should flash. Now you can check the status of each dishwasher program by pressing its button. Now you can run the full test cycle = Press the POWER SCRUB PLUS and REGULAR WASH buttons again. The dishwasher will start up and when the cycle has ended one, if you have no display panel on your dishwasher model the indicator lights will illuminate if a malfunction was detected as follows -
CLEAN - A temperature sensor fault. If this is the case then the test cycle will be very short as the dishwasher will terminate the test once it's been detected.
RINSE/DRY - A water sensor/filling fault. If this is the problem then the test cycle will not complete as the dishwasher cannot detect the right level of water, the dishwasher will just keep filling and draining again.
WASH - A heating fault. Check your heating element.
If you do have a display panel on your Bosch dishwasher then after the cycle is complete an error code will be shown if a fault has been detected. The error codes are as follows -
0 - No errors have been detected.
1 - A water sensor/filling fault.
2 - A heating fault.
4 - A water filling fault. This can also appear as F on the display during a normal cycle.
8 - A temperature sensor fault.
When troubleshooting your Bosch dishwasher, running the above test cycle is a good start in diagnosing the problem and should give you an idea of where the problem lies with your Bosch dishwasher and what fixes and repair are in order. Our general troubleshooting page will give you some ideas on other things to check on your dishwasher. Good luck!

Open the door, look along the top stainless on the door and you should find the ENr number (model number) etched into the stainless, may need to give it a wipe and look at an angle to read it. Post the ENr and that should help with diagnosis.

see this causes and fix it. God bless you
Thermal Fuse If the dishwasher won't start the thermal fuse might have blown. The thermal fuse helps to prevent damage to the dishwasher by turning off power so that it doesn't overheat. Once blown, the thermal fuse will have to be replaced for the dishwasher to work.

Door Switch The door switch, or switches, are sometimes called interlock switches. The door switch prevents the dishwasher from running while the door is open. If the dishwasher won't start, the switch or switches might be defective. To access the door switches, remove the control panel or inside door panel - depending on the model. They can be tested for continuity.

Main Control Board The main control board provides power to nearly every component of the dishwasher. If the dishwasher won't start the main control board might be defective. YOU should first check for more common parts. Many times control boards are replaced unnecessarily because the problem was not diagnosed properly.

Touchpad and Control Panel If the touchpad is defective, the control board might not get the signal for the selections made. If the dishwasher won't start and the display doesn't seem to change properly when the buttons are pressed, the touchpad might need to be replaced. On some models the touchpad and control panel are sold together and will need to be replaced at the same time.

Touchpad If the touchpad is defective, the control board might not get the signal for the selections made. If the dishwasher won't start and the display doesn't seem to change properly when the buttons are pressed, the touchpad might need to be replaced.

Timer The timer allows power to flow to the proper parts at the proper times. If the dishwasher won't start, the timer might be defective. Keep in mind that timers are often misdiagnosed as the cause of a problem. Check other components first before replacing the timer.

you need a water valve if the overfill float is not malfunctioning

Well the issue sound as if it were the timing unit. Some times work some times doesn't is a common symptoms of a timing unit. If you get the panel off take the timing unit and have it checked.

Here is what I found that makes my bosch dishwasher come on. It has the same problems as the OP. I pick the cycle I want press start. The DW will sound like it's trying to drain. I let it run that cycle which takes about 30 seconds. It then starts another cycle that sounds different from the first and when it stops I turn the DW off and then back on, it resets and then it starts the wash cycle. I've done this twice and it has worked both times. I do not know what is causing this but it's better then what I had to do to get it to reset.

After 3 seconds of reset (start), turn the dishwasher off, wait a few secconds, turn it on, and use the arrows to select the washing mode (try Auto, perhaps) and see if this solves your problem.

Can be that you have a leak somewhere.
At the bottom is a reservoir with a plunjer , wich switches everything off when this reservoir is full.
This is to prevent , that your kitchenfloor gets wett