Trailblazer a/c voltage question

My dad's 02 Trailblazer is having an issue with it's a/c system. When switched on, the compressor clicks on and off continuously (and within 5 seconds of each other), and the vents blow hot air. When I scanned the a/c pressure voltage, it was between .9 and 1.2 on the vcm scanner pid.

Is this low? If I remember correctly, my Cobalt SS was around 4.9v or something like that for the pressure, but not anywheres near 1. We just had it recharged, so my assumption would be that there is a leak somewhere in the system and that the Freon leaked out.

Can anyone confirm the voltage? Or have you heard of this problem before on early model year TB's with the 4.2?

Thanks in advance.

you have a leak, fix and recharge.

That was my first guess as well.