Replaced sensor in rear and front driver side sensor since I found the wire broken the light still comes on but at least the speedometer works right away now an I missing any or I need to go get the abs reset at the dealership
If you lose the connection to the sensor on top of the rear diff. the CEL lights and speedometer does not work and ABS fails.
I had this on my 2002 Export CRD likewise due to a bad connection at the Diff Sensor.
Fixing the connection got the speedometer to work but the CEL stayed ON for about two weeks of driving before going OUT...may be the same for you!