2002 kj

Hello, I have these two distinct noises coming from the rear of my 2002 KJ 3.7L V6 automatic. The first is a continuous hissing noise that seems to be coming from the rear axle/differential area. Some research lead me to believe that perhaps it has to do with vacuum tubes or fuel vapor tubes...

I'm wondering if anyone has suggestions on what scan tools will work on a 2002 KJ, specifically for diagnosing SRS and ABS, which I'm starting to understand that the less-expensive OBD2 scanners can not do. Also, I've checked the vehicle coverage on scan tools that can perform that kind of...