I don't think finding the problem at the harness connector end of things is very common at all. Except for one, all the CPSs I have changed have had a split in the insulating sleeve of the pigtail right at the sensor. The rest is moisture history.

I will say this: There is a correct way to route the upper end of the pigtail, and it involves the brass clip on the firewall seam above the valve cover. I like the plug itself to be in the clip, and I've seen enough cars set up like that to suspect the factory shipped them that way. It keeps the connector still and leaves slack for the cable to flex as the engine moves.

The one CPS I found failed at the top, as opposed to the bottom, had the cable passed through the clip, looped once, then plugged in. The plug was tucked behind the wiring harness further toward the driver's side. Someone obviously thought it was more important to keep the pigtail away from the engine hanger bracket than to allow for slack. The clip had completely worn away the cable sleeve, right down to the wires.

DS