Dunno whether it's the same as the one on a x20xev?
I hacked into mine to see whether it was causing my troubles a couple of months back. Was surprised how nicely engineered it was internally. If it is the same type, I could do resistance measurements on mine, but I suspect that as long as you get a smooth change of resistance with rotation of the spindle, the absolute ohm values are uncritical (pretty sure it's used as a potential divider, so just returns a proportion of the input voltage). An analogue ohmmeter would be ideal for checking this but...
...my bet would be a connection/wiring problem to it, not the TPS itself.
I bought a cheap secondhand one (before I'd got inside mine) which proved to be identically good. As The Boy says above.
Edit: FWIW, just measured the one I hacked into, it's a Bosch 0 280 122 001. It seems to be a total of 2160 ohms between terminals 1 and 2 (unvarying with shaft angle). If you measure between terminals 1 & 3, or 2 & 3 you see a range of 928 ohms to 2860 ohms as you turn the part the spindle goes into. Obviously it varies the opposite way depending whether you're between 1 & 3 or 2 & 3.
I guess there must be a 'padding' resistor (~220 ohms) at either end of the track, and (a 700 ohm) one between the wiper and the o/p terminal, to explain these numbers, vaguely remember seeing such things but I glued the lid back down, so can't see any more!