Good question.
Here's what I think.
If you have 4 wheel abs (I think all 02's do??) you have one sensor in the rearend, and one on each front wheel. If you are only setting the 0500 code then it will not be one of the front ones (they will also set a code for the abs).
If the 0500 is only popping up once in a while, I wouldn't lose much sleep over it. I always set that code after driving on snow or ice in 2x4. The front sensors are getting a different speed value than the rear sensor and confuses the computer.
That's my best shot.
Matt