Hi guys, i have recently bought a R230 SL350 2005 and getting to know the vehicle. Something i have noticed is a noise coming from the left hand sideof the boot the PSE unit i believe? It seems to be going through a cycling process? I have no warning lights and everything on the vehicle seems to work ok. Having done a bit of research i have established that the hydraulic resevoir is on the minimum mark but not below it, so not sure whether this would cause the PSE unit to be cycling? Am i imagining things, is this just normal or is something up? Any help appreciated. Cheers