Advancetrac works by utilising the ABS sensor's signals to determine how fast each tire is spinning. If one sensor gives a zero or weak reading, the vehicle automatically figures that it is now sliding out of control.
Advance trac will see for example.
Front right tire-300rpm
front left tire -300rpm
rear right tire - 300rpm
rear left tire - 300rpm.
Now lets adjust the right side to say 150 rpm. Now the advancetrac sees that the left side of the van is moving twice as fast as the right. Thus the vehicle assumes its in a slide to the right and will apply the left brake to adjust itself.
Advancetrac also works when you take off. If it sees your front left tire moving signifigantly faster then the front left, it will reduce engine power automatically to regain traction.
Front left - 0 rpm
front right - 350 rpm
So if the front right sensor is out of wack and sends a 350 rpm signal at stop, then engine belives that tire is spinning on ice and reduces power automatically.
my theroy is that you have a n/s wheel speed sensor (aka the ABS sensor) on your front left or right end. They are near the outboard CV Boot.
As for the rattling noise. Pretty much normal. more pronounced with the a/c or defrost on. Comes from the ac compressor clutch. Its like the ford power steering whine. It just does it. | 
