TDI PD Camshaft Position Sensor driving me crazy

[BFleming]

So I've been looking at an error code on my 2008 Passat 1.9 TDI for months now, saying there's an intermittant signal in the camshaft sensor. I'm getting about 100 Ohms of resistance across pins 1 & 3 on the old one. I bought a new one from GSF & now it's saying 'no signal'! It's like it's a dead sensor (Delphi). No resistance across any of the pins. The car still runs well, but takes 5 seconds of cranking to fire - same with the sensor unplugged.
Bought a new one from ECP tonight & although not yet fitted, there's no resistance across any of the pins again. So rather than go through the ballache of fitting it, I wanted to ask if anyone has any experience of such things?! I've always had a resistance reading of some kind from hall sensors, but these two new ones are dead.
Thanks guys.

[BFleming]

I got it sorted. My original sensor was throwing up a constant error, the GSF one I bought was dead, so a replacement came from EuroCarParts which solved the problems. The car will run well without this sensor, just starting isn't instant! Seems better on fuel with the new sensor too. It wasn't heavy before, but it positively sips now (close to 60mpg).