Becuase I have seem the parking senor light on my dashboard but obverious mine does not come with parking senor. I knew other years they have it. but how about 2000?thank you

 

Rear parking sensor was from 2001.
There is no "paking sensor light on the dashboard" for it.
The sensor on the dash is I believe part of the automatic climate control system

 

on my speedometer in the middle,there is a litte "car" at the lower left side?of course it never turn on

 

What you are seeing is actually part of the XK8?R Instrument Cluster. They share clusters, and on the XK the light is for the active cruise control, which is something I'm surprised Jaguar never put on the XJ's. Basically it senses when a car is in front and automatically slows the car down to match the slower vehicle.
Hope this helps!!

 

Stu, thank you for your explanation. eyeopening to know that but also disappionted to realized that XJR does not have the feature