Power steering maintenance required

First hello to all I would need help if it is possible.And I drive a Volvo V50 BJ.2005 2.0D 136PS and now have an error from the board computer ehalten.Servo steering maintenance required ! Ok I found out that the servo pump did not work anymore, so a new servo pump bought and built in, everything ran without problems Now it’s so that the error still remains and the servo also doesn’t work But you can hear that now the servo pump is running or it makes noises. Is it so that I don’t know what I can still try or should Villeicht is here who had the same problem before. So I would be very happy if someone could give feedback about this Lg monkey