Is the pump running for the normal length of time (7-10 seconds) when you open the driver's door after the car has been at rest for a few hours?
I'm wondering what triggers that fault code - whether it really is a faulty relay (how would 'it' know?) or whether it's triggered when the pump runs for longer than expected. Check the Selespeed fluid level and top it up to the seam in the tank if necessary.
If the pump is running only for short bursts, then it's likely to be the accumulator at fault. See thread
http://www.alfaowner.com/Forum/alfa-147-156-and-gt/327000-baffled-by-a-selespeed-p1769.html and other threads linked therein
Actually, it makes sense to me now that a high pressure reading will trigger that relay fault code, as the assumed cause of high pressure is that the relay has stuck 'on' and the pump has continued to run for longer than 10 seconds.
The reality is that the high pressure results from the pump running briefly against a failed (flat, discharged) accumulator. Use
MultiECUScan to check your pressure. It should be a gradual rise over a few seconds followed by a steady decline for two gearchanges, then the pump should run again. If it is spiking up and down much quicker than this, accompanied by odd noises (clunks and groans), then the accumulator is the problem.
The accumulator is part number 71751195 and I'm fairly sure there is stock in Cambridge at
www.fiatparts.co.nz, 07 827 8918.
If the pump seems to run for the correct length of time, sounds normal, and yet the pressure readings are irregular, then perhaps a faulty pressure sensor (reporting a wrongly-high reading) is a possible cause. Seems less likely, but always good to have a backup plan/next thing to try.
I think you do have a pressure problem though, as two particular actions consume more fluid pressure than anything else:
1) Selecting reverse (both gearchange actuators full-travel), and
2) Holding the clutch disengaged while 1st gear is selected.
And those happen to be the circumstances you've reported as being a problem. Soon, it will probably be unable to select any gears at all, so it's worth fixing
-Alex