CAM sensor

On a 1993 to 1999 A3 Jetta:

The camshaft position sensor is in the distributor (the hall sensor).

To remove & replace it, you need to remove the distributor.

On a 1999 to 2005 A4 Jetta:

The camshaft position sensor is located behind the camshaft sprocket.

You need to remove the timing belt & the camshaft sprocket to
remove & replace the sensor.

In both cases, you need to be sure that TDC for #1 does not get
moved, or if it moves. That everything is put back to the correct
#1 TDC alignment points.

Thomas