I, too, have the problem of non-starting. I have tried many different things. It all started when the car battery went dead. I recharged the battery, and the car operated normally for a couple of days. The lady that owns the car tried it again two days after she had driven it last, and now the FOBs will not open the doors. After opening the door with the key, with my foot on the brake, the key in the on position, the dash lights come on, the shifter will not come out of park, and nothing happens when turning the key to start. I have checked every fuse, and they are all good except no power to horn #2. I haven't checked the relays. The FOB batteries are new. I even tried a brand new car battery, and that didn't help.

 

I failed to mention that it is a 1996 XJ6.

 

I, too, have the problem of non-starting. I have tried many different things. It all started when the car battery went dead. I recharged the battery, and the car operated normally for a couple of days. The lady that owns the car tried it again two days after she had driven it last, and now the FOBs will not open the doors. After opening the door with the key, with my foot on the brake, the key in the on position, the dash lights come on, the shifter will not come out of park, and nothing happens when turning the key to start. I have checked every fuse, and they are all good except no power to horn #2. I haven't checked the relays. The FOB batteries are new. I even tried a brand new car battery, and that didn't help. The P for park is illuminated with the key on and the brake lights work. Also, the gas tank lid is locked shut and will not open.

 

Hi Jag?,

I have moved your posts from another thread to your own thread. Posting about the same issue in multiple threads is frowned upon because it leads to confustion regarding what possible solutions have already been offered by other members. It's far better to have all the replies in the same thread.

One possible solution you can try is to use the key to lock and unlock the driver's door a couple of times. Sometimes the security system gets out of sync and this will resynchronize things.

For a lot more ideas, check this thread compiled by aholbro1:

Gentlemen: (No) Start Your Engines

Cheers,

Don

 

I apologize for starting a new thread. Thank you for the information. I have tried locking and unlocking, but I'll try some more. I am slowly learning more about this car even though I haven't solved the issue yet. I'll locate the starter relay and switch it out next. I've read about the ECM, but I am not sure where it is located.

 

The starter relay is in the group of relays on the left side of the engine compartment:


This and other helpful information is available in the Electrical Guide, which you can download at the link below courtesy of our member Gus:

Jaguar X300 Electrical Guide 1996

Cheers,

Don

 

This car is a strange beast. Today was the first day that the car started since I've been trying to diagnose the starting issue. Every other day when I looked at the red security light, it was not flashing. Today, it was. I didn't do anything other than walk up to the car with good batteries in the remote. The interior lights came on for the first time in a week when I opened the door. The car started right up, but I am still having trouble with the alarm system. It is very erratic getting it to arm. I'm beginning to think that it is a bad actuator in the driver door. The key FOB's worked perfectly part of the time, but not always. At the end of the day, the car would start, but the FOB's would not lock the doors, nor would locking the door manually with the key arm the security system. The lock button on the dash only worked one time.
Are the FOB's critical to the security system? I suspect that one of them is not working properly because even with good batteries in it, the lights on the FOB do not always flicker when pressing the buttons.
Thanks,

John