Brake pad warning

[Joe Yakubik <75363.2524@CompuServe.COM>]

Having just replaced the pads/pie pans (UFO rotors) in my '91 200tqw I can throw
a little light onto the subject:

The sensors (and, I suppose by default, the system) measure continuity.  The
sensor slides into the pad with its little sacrificial wire run through a piece
of plastic/bakelite stuff.  The rotor eventually wears through the plastic and
exposes/cuts the wire(s).  I include "exposes" because I think when the disk
hits the wire it shorts it to ground with the net effect of zero continuity.  

To check if you have bad sensors or bad connections further upstream should be a
fairly simple process:

Unplug the connector from behind the wheel, then apply a jumper across the two
pins.  run a self test.  if you still get a warning then you do not have
continuity at at least one other wheel.  Leave this jumper in place (it's
pretending it's a "good" sensor)  then repeat at the other wheels.  When you
have four jumpers in place and still get the warning, then the trouble is
upstream.

For the people who have "intermittent" lights then stay on steady, it could be
the sensor connection.  When I pulled mine off, there was significant moisture
in the car-to-sensor wire plug connection.  Alternatively, it could be one of
the AG's (Audi Gremlins) chewing on that wire somewhere in the least accessible
part of the car.

Joe Yakubik.

un***scribing for two weeks for a European vacation "...look kids, the Houses of
Parliament, Big Ben...the Houses of Parliament, Big Ben....the Houses of
Parliament, Big Ben..."