If itys a 1.8 four cylinder...its on the exhaust manifold, just prior to the downpipe. It looks like a spark plug screwed into the exhaust manifold with black wiring to it.
Farthest point right before the catalytic converter.
its incorporated into the maf sensor.
Where is the crank shaft sensor located in a Audi a6
Where is the answer
Disconnect the wires, and unscrew the O2 sensor. You might want some wd-40 to soak up the sensor's threads before you try to remove it.
Inside the airbox.
Probably the speed sensor has crapped out. Or the module has.
No.
turnes on and off the internal sensor for the alarm
Assuming that the brake pads were just changed and the sensor is still on, Perhaps the sensor wire was broken during installation causing the sensor to stay on. Happened on my 2001 a4.
the answer is ricky bobby
Over by the air filter's box.