Sorry to be un-kit related but......
Neighbour has just spent a heap of cash having a new electric power steering pump fitted to his 2008 Astra H but it hasn't fixed his car. So he came knocking on my door.
A drive showed stiff steering with no self centering. Disconnecting the pumps earth lead made the steering a whole heap heavier so we know that's doing something. There's no obvious damage or leaks on the rack. The battery and alternator holds a healthy 13.9v. There's no undue noises.
Next step is to fit a new rack which looks to be an arse of a job! There's a choice of three different racks for his car which I've narrowed down to two for certain and of those two, I can deduce one to be the most likely going by the turns from lock to lock.

Question is..... Before he blows another heap of cash, is there a way to test the PAS ECU? Is there a torque sensor or a position sensor?
Is this a common fault on these cars?

Cheers folks.