if the brake pedal is hard you might first want to check if the mineral oil is full, get the castrol mineral oil for jaguars with the attached pump. Make sure the oil level is green with a black dot, if is clear with a black dot then the container is empty and it needs oil.,, Good luck bud..!!
The brakes?
There are usually two warning brake lights on the dashboard. One is for the Hand brakes if you don't release completely it it will stay on. The second light is for brake failure. If it stays on it means worn out brake pads, brake fluid loss and will require early attention
Your brakes are failing
check fluid level
Light is usually comes on, when there is a problem with pressure in brake lines. Inspect the brake fluid level, and check for leaks.
your park brakes are on
fix your brakes
As long as the red " BRAKE " light is not on in your dash you still have " normal " brakes even with the ABS light on
You probably need to change your back brakes.
In most new cars the parking brake light is also activated when the linings of your brakes wear out.
You have stepped on the brakes
Is it the parking brake light or the ABS light? is it red light or amber?