So just recently I had the P0520 code for the oil pressure switch / sensor. On my 2007 XK hemi it is located up behind the oil filter. I bought a new unit from Advance and bought their 1 1/16" special socket for removing these sensors. Well, I wanted all to know that socket does not fit. I went back and exchanged it for a regular 27mm deep socket which fit perfectly. It's actually a pretty simple job to do with relatively good access. Just make sure you have a long extension and one of those swivel adapters since it's not completely a straight line to get to.