For the F35 error code you need to check if the pressure hose is fixed correctly, check if the airtrap is not blocked, check if the pressure hose is not blocked. Once all the possibilities have been checked I recommend replacing the pressure sensor.
I am sending you step by step access instructions from the service manual showing the location of the pressure sensor & airdome. Be sure to check both airtrap & pressure hose before replacing the sensor.
Remember to disconnect power before attempting access & use caution around sharp metal edges.
The pressure sensor is secured to the right hand side of the top section of the washer.
Please see the attachments below for more instructions.