Hi all,
My w210 Advantage steering is very light, it is good for low speed but once on the free way it feels way too light.

I did check the electric steering sytem with Star diagnostic, light and stiffer feature works just fine but in reality when the car run above 10KM steering doest get any stiffer as the way it should
Im assumed that steering rack is fine (no leaks) but dont know why it doesn't get stiffer at above 10 KM.

Any suggestions?

Thanks in advance, appreciate your suggestion.

You assume there is no leaks - have you actually checked the fluid levels in the PS reservoir? no mention of this
When was the last time you flushed/changed the PSF?
Have you checked your tire pressures?
History on any recent changes/issues?