2005 xc90 Error codes from Engine warning light

[Hiltonindurbs]

Hi
My 2.5 XC90 started but had no power this morning and gave a message "Engine system service required". I stopped and restarted and she went fine all day,but the message is still there. While googling about it, I found a site that says that to find out what is wrong, I can get an error code without an OBD11 or VIDA or DICE by holding the read button on the left steering column stalk and the trip meter reset button for 10 secs. I tried this and get 042 on the screen. When I let go of the read button 045 appears. Can anybody tell me what these mean. They bear no resemblance to the OBD11 codes or Volvo's DTC codes.
Thank you