The 4SNS/x/x/x failure is a logic board error (which you have already figured out, eh?)
The important part is the '4SNS', which would indicate a problem with a sensor on the logic board. You can try a power manager reset, and run the test again. The power manager reset will be somewhat different for each Mac model. Most recent models can be reset by unplugging everything, and removing the battery on a laptop. Press the power switch for 5 seconds or so. Some Macs don't need the power button, but it won't hurt anything to try that, too. Leave a network cable disconnected, and other external hardware, other than a mouse and keyboard, should not be connected. Power cord and battery (if a laptop), and try the diagnostic test again. If you still get the 4SNS failure, then the logic board will be the culprit.
Serendipity is a lucky guess !