Boolean IF Statement PLEASE HELP!

So i was making a simple car System, and for the most part it works great (I havnt done parenting the player to the car yet) but you could click f and enter, BUT How do i make the code know When IM In the car, so when im in the car the ExitUI will appear

#pragma strict
var Player : GameObject;
var Car : GameObject;
var EnterUI : GameObject;
var ExitUI : GameObject;
var Enter;
var IsInCar

function Start () {
if (Car.activeInHierarchy(true))
{
IsInCar = true;
}

}

function Update () 
{
if(Enter == true && Input.GetKeyDown (KeyCode.F))
{
        Player.SetActive (false);
		Car.SetActive (true);
}
		if(Car.activeSelf (true) && Input.GetKeyDown (KeyCode.F))
		{
		ExitUI.SetActive (true);
		Player.SetActive (true);
		Car.SetActive (false);
		
		
		}
		
}
function OnTriggerEnter (other : Collider) 
{
		Enter = true;
		EnterUI.SetActive (true);
		
}
function OnTriggerExit (other : Collider)
{
EnterUI.SetActive (false);
}

Errors

Assets/MyScripts/EnterCar.js(17,24): BCE0077: It is not possible to invoke an expression of type ‘boolean’.

Do you read your errors ?

if (Car.activeInHierarchy(true))
...
if(Car.activeSelf(true)...)

You are trying to invoke a function while activeInHierarchy and activeSelf are not functions but attributes of the GameObject class…

Just remove the (true) from these two expressions.

you have no semicolon after

var IsInCar