I recently experienced an issue with my 2011 XJL where the engine fails to crank when I attempt starting the vehicle. The gauges cycle but the engine fails to turn over. The shifter does not rise from the console either. There are no fault messages that appear on the instrument gauges, I have confirmed that the battery has the proper voltage and have even attempted jumping the vehicle. Can anyone please offer suggestion as to what the possible issue is?

 

I may be way of base here but if the key isn't authenticated by the vehicle you wont get crank or shifter rise. Can you open and lock vehicle with the key?

 

I recently had the same issue. Often in the morning, it wouldn't start. Would need to get out, lock and unlock car several times before it would start. I was certain it was due to the car battery getting weak, so I took it too the dealer, and they suggested it was the battery in the key fob.
Seems the problem is two fold. First when the battery in the fob weakens to a certain level, you can still lock and unlock the car but it isn't strong enough to allow the car to start. I replaced the battery twice (first set was supposed to be good till 2022 but wasn't strong enough to work properly). and after that works fine. The other thing I noticed is that the amount of pressure on the brake required to start the car varies. In the morning the pedal is very stiff and I need to press down hard. I was pressing down on it with the same amount of pressure I was used to during the day, the car wasn't starting, never thinking that I needed to press harder. During the day the pedal has a lot for give to it when I start her up. Before these two changes, it wasn't starting right up half the time, but now it always works fine.

 

https://www.jaguarforums.com/forum/x...-works-130713/

1st...Start Button
2nd...Press Brake Pedal

 

First off, THANK YOU to those of you that took the time to respond. It is folks like you all who truly make these sites the value that they are. I sent emails to a couple of people who I had hoped would respond but no such luck with them. Secondly, the issue was due to me apparently having to press harder on the brake pedal. I found that by applying firmer pressure to the brake pedal and then pressing the start button, the car started. I find this odd because I have never had to press down as hard however after starting the car, the pressure required to the brake is not as much now. So all seems to be normal now. Again, THANK YOU to those who responded.

 

If you hold your foot on the brake pedal for a while after you turn off the engine, the brake boost gets used up. When you next try and start the car there is no brake assist so you have to push mechanically (ie much harder). Once in a while my wife would stay in the car after turning off the ignition to finish up a conversation. And she kept the brake pedal pressed in. Next time we wanted to start the car it was hard!