Data LifeGuard Diagnostics. Is there a place i can find explanation to my error?

What is the use of making a diagnostics tool if you can not find what the meaning of the errors? I have WD5000AAKS. when i trying to run the Quick test I get: Quick Test on drive 2 did not complete! Status code = 7 (failed read test element), Failure Checkpoint = 65 (Error log Test) SMART self-test did not complete on drive 2!