Are you getting a P0480 along your P0528? If it's just a P0528 you're getting alone, it likely means your PCM is not reading the actual Fan RPMs, but still operational (which is the important part). If you were getting a HARD P0480 and P0528 together, I would say the fan blade ate the actual harness. The dealer level test of its operation, is to run the engine at 2500 RPMs STEADY. Take active command of FAN_VAR Duty Cycle from 0% to 100%, and fan speed should instantly rise to 2800 RPMs and beyond.

In the OP's case, if I were to guess, I would say that it would likely pass the above described test, but not indicate the FAN RPMs.