I've got a 1995 XJR with a strange problem with the security light on the central locking button. As far as I can tell all the keys and fobs work as they should. However, when I insert the key and turn it to position 2 the security light blinks continuously at approximately half second intervals. The blinking continues when the car is started and does not stop until the ignition is returned to position 1.

Recently the ECU has been replaced by an independent Jaguar mechanic in an attempt to rectify a mystery high idle problem (I will address this problem in a separate thread). This failed to fix the issue and to my understanding my original unit was put back in. Could this have something to do with what's going on?

Any ideas are greatly appreciated. Hopefully I'm just missing something obvious.

 

High idle? Or throttle hanging up and not returning to idle?

If the latter, you probably need to do the throttle spring TSB.

 

Turn the key to position 1--when all the dash lights go off, what happens to the check engine light?

It's supposed to stay on. If it goes out, the car has been "immobilized" and I would bet that your security module was reinstalled incorrectly. (Note: the car will still start, the immobilization feature probably does not work if the unit isn't installed correctly!)

Why might I ask did your mechanic think of checking the security system for a high idle?

 

The check engine light stays on. I'm planning on going through the security manual this weekend and making sure all the features listed in there seem to work.

Excuse my ignorance but is the ECM separate to the security module? The mechanic tried swapping out my ECM for another just to make sure it was not the culprit.

 

The ECM is separate, yes. The security module is located under the carpeting in the trunk, right by the fuel filler (at least in left-hand drive cars). It could be a wiring problem causing the light, but I would definitely make sure all the features work. At least we can see that it's not confused, potentially immobilizing the engine.

-Try pressing the lock button again after locking the car and setting the alarm--headlights should come on for 30 seconds
-Hold either the lock or unlock button for 3 seconds, panic feature should engage
-Roll down one or multiple windows. Insert the key into the driver's side door and hold in the lock position; the windows/sunroof should all close as you hold it there
-Three presses of the unlock button should unlock the trunk on the last press
If you're up to the task, remove one of the door panels and disconnect the cable going to the central locking module (big black box that has a rod leading up to the lock that you would press in the car to lock the door). Ensure that locking the car doesn't lock this door, then lock the car with the remote to arm the vehicle. Open this door; the alarm should go off. If not, I would wager a problem with the security module I mentioned before. If all seems well, I would bet your problem is coming from the wiring behind the center console. In that case, you'd have to remove the "ski slope", then take out the radio/climate control combination and see if any wires are frayed.

There was a TSB about this, and if your car was recalled for it, all the wires should be wrapped in heavy-duty tape. If not, I would take it upon yourself to do that, as it can cause problems with the interior lighting in the future.