Just purchased a 2002 Sport Utility Blazer, 4WD, V6 4.3L engine from an estate sale. Hooked up my Actron CP9580A Code Reader. It showed P0101, P0300, and P0155. I may be able to handle these. My problem is when it looked at the Transfer Case option, it said LINK ERROR. What do I look for to proceed? The transmission seems to be flakey, so I want to know how to diagnose the problem.