Fault codes

Can anyone shine any light on these two codes?, P0011 camshaft position actuator A bank 1 Timming over advanced, and p1171 cant find a reference for this code my local garage who fitted a timming chain approx 13months ago says he thinks its low oil pressure and said I need to get this checked out first but he has nothing for testing it?????????!!!!!!!!!! we forked out £600 for the chain to be done and took it back with a noise whilst under warranty but at that time they said they could not find anything wrong now its just out of warranty very annoying!!!!!! how difficult to fit a new pump as its part of the timming chain cover???.
any help greatly appreciated.
I decided to top the engine oil up with stp oil treatment then give it a run on the motorway the engine management light has come back on, and the two codes have re appeared////.