IACV setup with pscan?

Hello, on my Rover 45 1.4 from 2002 I have some issues with the IACV after replaced it (somedays the idle goes 1600rpm during driving with warm engine and then goes down with a touch or pedal), someone tell me to setup the step to 21 - 25 using a tool, I read something I can use Pscan for doing this setup but I don't understand the whole process. Can someone, please explain me how to do it with the Pscan?

I have no idea what your 45 really is configured,  as I've not actually seen one, they're very uncommon here in Oz, but is it fitted with the plastic throttle body?
If so that might be the cause of your problem, on the early Fs with the plastic throttle body, the damned things would eventually warp slightly when warm, trapping the butterfly valve and causing a high, idle.........and with a quick tap of the accelerator it might settle to a proper idle again. 
The fix is to bin the plastic rubbish and fit an alloy one.

There may be some additional support here,
https://www.mg-rover.org/forums/mg-zs-2001-2005-rover-45-400.102/

if touching the pedal sorts it out, then it's a mechanical issue, not electronic / ECU, and pscan will not be able to solve that.

...............which brings us back to the potential throttle body issue!

I doubt the original SU plastic TB would still be used on a 2002 45, I would be looking at the pedal trunnions for warn bearings, assuming that system is similarly to ours.
As the throttle cable is so short, in comparison with our cars, it’s less likely to be sticking, although a squeg of lubricant might help.
M

They might've been using up old stock on poverty pack spec cars. I wouldn't put it past the bean counters at MG Rover

Fair comment.
M

In our family we have a year 2004 Rover 25 with the 1.6 K series, which my daughter is now using as her daily car.

When I used to drive the car it would at times, gradually increase its idle speed all the way up to 2000 RPM.  It would be worse if I put a some load on the engine whilst at idle (for example, drive up a slope on idle).

The way that I had to "reset" it was to stamp hard on the accelerator, just briefly and equally suddenly let it decelerate to idle.

Since my daughter has started driving it daily, it just doesn't happen.

My feeling is that something was sticking in the idle control system, and the sudden deceleration from high revs to idle was unsticking it.

I do have the aluminium throttle valve. I noticed when I'm driving and engine is warming, everytime I change gear, idle goes down quickly, untill the engine is warm. When is warm, when I change gear, idle stay high a bit and goes down slowly, sometimes stay 1600rpm (in this case, I touch the pedal and it goes down), after that, when I change gear, the idle goes down quickly again. Before replace it, I cleaned the original one and everything seemed ok, after some days the issue came back again. I replaced it with a second hand one, first week the car was perfect, now the same issue come back.
I ask to MG Rover forum and they told me about the setup of the step motor with a tool, that's why I asked here because I have the pscan

Reset the IACV

Also check  THIS POST  for unstable idle problems.

Thank you so much! I try tomorrow the first tip (I did the reset but pressing the pedal fast instead of slowly and wait only 10 seconds). Then I'll try the second one with the pscan. Still many thanks!