Changing AC pressure sensor

[komichal]

Hi folks,
my AC sometimes takes 5-10 minutes before it starts blowing cool air (but it is like 1 case out of 5).
Local AC service center inspected the system, found nothing extraordinary (they measured the pressures - all OK, they had to add some "freon" as well but just a little). But they do not have TechStream so they could not check the data there.
But I do have TechStream so I noticed that the readings from the pressure sensor are a bit erratic whenever the AC problem happens. So I am going to change that little thing.
I have read probably all the topics around it here on yarisworld - guys you are awesome! Now I know I have to get myself one piece of 499000-7141.
The last thing is the change itself. I have learnt on the internet that "most cars do have a ball valve on that sensor so it can be replaced without evacuating the AC system". Is it also the case for Yaris? (2007 5-door 2SZFE 1.3 64kW) Or do I need to drop by the local AC shop one more time to do the change for me? Or if I am fast enough, can I replace the sensors with just a little bit of hisssssssing from the line that may have no impact on the functionality, especially when it was recently topped up?

Thank you in advance, lads!