So does anybody have an idea on what else it could be besides a sensor problem?

I had a look on WIS and the sensor is definately on the differential, not on the rear of the transmission as I thought.

On WIS the connector shown isn't a plug and socket as you would think, its a terminal block with ring connectors.

Also, it says that you need to remove the seat bench and backrest, so if you haven't already looked behind the backrest, it could be there.

Looking in the fault table, the fault for 'ABS lamp coming on whilst driving and does not go out again' is 'Wheel speed sensor cable interrupt'

So again, you really need to check the sensors and the wiring. Sensors need to be checked with an oscilloscope for a definative answer, but as previously suggested, a multimeter set onto an AC scale may give a reading when the wheel(s) are spun.

Just wondering, is there a way I could test the rear sensor for a signal at the ABS unit itself, like using the multimeter on the prongs of the main plug going into the ABS unit, and avoid having to find the plug behind the seat bench? If so, does anyone know what number on the main ABS unit plug corresponds to the rear speed sensor?

Pins 7 and 9 on the ABS computer (not the hydraulic unit).

Oh, and like I said earlier, you really need an oscilloscope to check the actual operation of the sensor. Do you know of a friend with one at all, or even a local shop?

You could even get one on the well known auction site usually for not much more than the shipping cost.

I finally got a chance to pull out the abs computer today, but the pins on the plug are flat and have no numbers on them. Just to clarify, did you mean pins 7 and 9 on the abs control unit along the firewall under the windshield? If so, how do I know which pins are 7 and 9 since the plug isn't numbered?

Hmm I'll check those pins with the multimeter I have as soon as all the snow melts away and it warms up a bit (We were just bombarded by a completely unexpected snowstorm!). If the reading is good, then I guess I'll get me an oscilloscope as advised to retest all the sensors. I just wanted to test the sensors with what I have available to see if I could find the culprit before obtaining an oscilloscope. Ill stay updated on my findings...

Thanks for the wire numbers!