OBD code 150 ?

Anyone have a clue what this code 150 represents?  Also, 1171 & 1174 popped up with it, but I understand what these codes mean.
 
00 Disco 110000 + miles. 
 
I am going to replace all 4 O2 sensors since they have not been.  The MAF was just replaced so I am hoping the O2's will take care of the "Bank too rich" codes". 
 
Still, I would like to find out what the code 150 means incase my Disco has other problems that need attention. 
 
Thanks!

Incase anyone else has this problem I finally found out that this code means "slow oxygen sensor response".  So, it seems like the O2 sensors I have on order should take care of the problem.   
 
 

Glad you got it taken care of! 

O2 sensors are always tricky for me...I always want to just replace em and eliminate the possibility, but they're just expensive!