Pump always on, lower pressure, water leaking

I have a Kärcher K 2.01

Recently, when turned on (= electricity switch on) but without pulling the trigger, it started to "kof", that is to turn its pump on and make the same noise as when you use it, but even when idle.

It did so in short bursts for a while.

Now, the pump is always on, even when you don't pull the trigger, there's a little less pressure (though still usable) and you can see quite a lot of water leaking out of the yellow box.

Is this repairable?

If yes, how?

Thanks