2010 C5 X7 Hydraulic Steering Pump Issue?

[harry-the-hearse]

I recently decided on trying to keep a 2010 C5 VTR Plus Nav 1.6 Hdi Estate (steel spring suspension) alive for a few more years. It has been a good reliable vehicle for last 10yrs ownership but needed new clutch and timing belt replacement, and steering had gone ‘Lumpy’ – 110,000miles on clock.

Clutch and timing belt replaced ok by competent local mechanics. Steering issue assumed to be the hydraulic pump but their regular refurbisher has just gone out of business so decision was made to try secondhand item off ebay.

Steering is still ‘lumpy’ - slightly less so than before – but won’t self-centre and is notchy when turning the steering wheel. Believe the correct fluid has been used.

My question(s) is(are); -

Are the symptoms truly indicative of steering pump failure; or could it be the electronics?
(All ball joints/track-rod ends/steering rack/strut bearings/steering column UJ, etc are known to be in good condition, even under load; and proper bleeding procedure followed)

Would putting a temporary 12v supply to the pump help decide if the mechanical part of the pump was working okay, or is there too great a risk of doing damage?

I have since heard that the electro-hydraulic pump needs to be coded to the specific vehicle in order to perform properly.

I have also been told that it is impossible to over-write the code in a replacement pump unless it is a brand new item.

If this is indeed true, can the electronics from the original pump be swapped over to the replacement pump?

Or, is there a firm out there that could refurbish the original unit as a whole?

Or am I stuck with Main Dealer prices? ...which could well be fatal to the project and would be a criminal waste of what is otherwise a good car.