Idiot lights
 

So my wife was driving the '03 xc70 for the last couple of months and last week she drove it home (about an hour) and when she got home she said it was making a tapping sound. I went out to discover that the oil was all but gone. long story short... I'm now having to replace the motor. My problem/question has to do with the oil-light on the dash. She claims That not lights or warnings came on. Has anyone had a problem with these warning lights and their sensors?

She lied. The low oil warning would have lit the light and displayed a message.