A generic code reader only reads DTC or Diagnostic Trouble Codes.
A scanner will scan the car. Keep in mind that KR is a GM Enhanced parameter and you should ensure that a scanner you are looking into getting will read the GM Enhanced parameters.
For example.. I have both Autotap and AutoEnginuity for the laptop. Had I ordered them as barebones stock applications I could read things like water temp, maf, O2 sensors..but KR would not appear. Since I ordered GM enhanced...I have KR and many other GM only parameters as well as the generic parameters.