Not long after i purchased a 1994 Granada Scorpio 5 years ago it wasn't long until the ABS light came on however, i have now diagnosed the fault which was due to a faulty NSR ABS sensor. Upon inspection the sensor showed resistance but generated no AC voltage whilst the wheel was rotated.
Trying to locate a new sensor has proved difficult although, i have now purchased a sensor via ebay for later Scorpio assuming it must be the same.
However, i cant help but think that the Scorpio type is of the Hall effect type that generates DC voltage and therefore is not compatible with the earlier Granada.
Should this be the case then the Scorpio sensor will be returned straight away of course.
I think the only way round the issue is to find a Sierra rear sensor and cut the plug off then replace it with the later Granada type of plug (similar to the type that's used on some brake pad wear sensors).

Having passed C+G Level 3 in Light Vehicle Maintenance & Repair i touched on all the various types of ABS sensors both passive, inductive & Active types.
The testing of early passive sensors is a straightforward task with a basic multi meter.