I have a 2000 Jaguar XJ8 that wouldn't start. It turns over fine but doesn't act like it is firing. We took it to a mechanic's shop but he doesn't specialize in Jaguars and said he would look at it anyways. He ran the codes and it is throwing U1135. I have done a little research on the code but can't come to a conclusion of what to tell the mechanic to try. From what I have found it looks like this code has to do with some kind of module in the drivers side door that controls a few things. Maybe it has something to do with an anti-theft system? Would this code be something that would stop the car from starting? Any help would be greatly appreciated, Thanks.

 

Sounds like a failing key sensor. Whether it be the module in the key itself or the reader in the cylinder of the module. Do you have another key to use?

 

No, I only have one key

 

Did you ever resolve this please? I have the same issue with a 2003 XJ6 V8, it just cranks and won't start with U1135 logged

 

Have you checked your CPS (Crank Positioning Sensor)? They can get dirty and not read the flywheel rotation, not allowing it to start.
Also check the wiring to it to see if it may have been damaged.
Do a fuel pressure check as well.