I have a 2011 Jaguar XJL that keeps having the alarm go off on it.

I have since started seeing messages on my car where it says the hood is open (it is not). It sounds like this was a common issue on the previous model XJ, but have found no one with the issue with the X351 model.

People mention two fixes for the previous version.

1) Short (tie together) the sensor so it thinks the hood is always closed

2) Replace hood sensor

I have looked at my car and I cannot find the sensor. I see some that might be it, but I am worried those also are airbag sensors (which I definately do not want to play with!)

Anyone happen to go through this? Can someone steer me in the right place to get this fixed? (Part number, and where and how to get at it).

 

deanolds, if you are only messing with the shock sensors on the car, messing with a single sensor is not going to trigger anything. It takes a minimum of 2 shock sensors to cause the airbags to deploy (even then, needs to be in a given direction, of a certain force, of ........). So, no worries there.

 

I am now having the same issue with my XJL. How did you resolve this?

 

replace the hood latch with the integrated sensor. Only way to fix it.

 

Had same problem of alarm randomly going off. Just replaced the hood sensor. Process was very similar to this video except didn’t have the same bolts to remove. Removed air intake shroud by removing the six torx bolts. Then just unplugged and pried off the old sensor beneath the latch and pressed on a new one and plugged it back in. Took less than 30 minutes.

 

Thank you Nick!
Short, simple and correct!
Learn something new everyday on this forum. I have seen many external plunger type hood switches and did not know Jaguar went even further and stuck it under one of the hood latches.
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The reason why plunger type switches dissapeared from hoods and doors and moved to the switches inside of locks itself, are that plunger type are very easy to bypass with flat object and open the hood/door without activating alarm.

 

Ok, so I might be way off track here. But indulge me.

A while back my 2011 XJL at ~30k miles started having an occasional alarm trip for no reason. Sometimes just in the garage it would go off. I wrote it off to needing a new battery, replaced the battery (it was about 7 years old) and considered it resolved.

Recently the alarm has gone off a couple more times in the garage. So I did some research here and learned how others had resolved the issue by replacing the switch.

Seemed reasonable to me, though I did find it odd to be happening with only 30k on the odometer. Although all of my prior Jaguars have had a few poorly designed parts in them so perhaps just one of those times.

I took a look under the hood to get an idea of how/where the switch is located. Not a big deal to get to the switch, just remove a few covers and such.

I could trace the wire running up to it with my hand. I do think that wire is a bit too taut but probably not causing any problems.

Well ok I will look into getting a switch and get back to this later. I closed the hood. Then...

I felt it.

It was very slight but yeah it is there.

Movement in the hood somewhere when I pushed down on the driver's corner. It made a "thunk" sound that I could repeat.

Very subtle but definitely there. So up goes the hood.

I look all over the latch area and nothing is loose. Then I look up at the driver side catch on the hood.

Grabbed and gave it a tug. And there it was. My thunk. I was not imagining it after all.

I go check the passenger side and no thunk over there, totally solid. Obviously, the catch is coming off for a better look.

When I got it off I found that I could pull on the rod and get it to move in/out of the mounting bracket on the side where it appears to have been a press fit maybe, not really sure.

You can see the amount of movement in the rusty ring. Regardless the movement was not supposed to be there.



So how to lock it in place to rid myself of the thunk?

Now that I know it is there, it would drive me nuts if left unattended.

The rod is an odd setup I think. It appears you can adjust it some, though I admit I don't understand exactly why only on one side.
It looks like I need to apply some tension on the loose side so it will snug up. The design of it made a nice space for me to wedge in a small block of wood.
I backed off the adjustable side a couple threads then inserted the block and retightened. All snugged up after that.


I reinstalled the catch and gave it a test push/pull. Can't feel it now.

So could this bit of movement be enough to trip the alarm? Maybe. After thinking about it the alarm usually went off after a long drive where things were very hot when parked. Perhaps the cool off and a little bit of flex in the hood would move that catch enough to trip the alarm. Might just take enough vibration. I don't know how it is made. Perhaps somebody can chime in on that.

Back to my original statement, I may be way off track here. But I figure the hood catch is better off from the effort. And I learned a little bit more about my car.

Now...I wait. If the alarm trips again, I will order the latch switch.

Either way I will post an update.

 

From the design it looks like the latch should be just tightened completely. I agree that having it be wiggly doesn’t sound ideal and could contribute to the alarm issue. Mine was easy to diagnose because I would periodically (albeit very infrequently) see the hood open warning come up while driving.

On mine the alarm hasn’t returned since replacement of the sensor. If it does come back, I’ll play with the latch. Thanks