So I've been chasing a niggling issue with a double beep intermittently on door locking on my 2010 XF SC. (With passive / keyless entry). So wanted to share a combined view of all the potential causes. Look to the end for what actually fixed it...

Symptom - occasionally (and then more frequently) on locking the door by pressing the button on the handle I got a double beep - then sometimes trying to open the trunk (and occasionally a door) the trunk button or handle didn't work. However pressing buttons on the key fob always worked without beeps...

Possible fix 1: Well covered on the forum - if trunk button stops working the wiring harness in the rubber boot to the right by the hinge can get broken wires in it. I checked but all were fine (have replaced that before a couple of years ago). To check, pull the rubber grommet off each end, cut the little rubber connector where it attaches to the wiring harness and slide it back to check all the wires.

Possible fix 2: Changed keyfob battery. Thought that fixed it but it came back after a week and then got a lot worse. Started to see smart key not found while driving too...

Possible fix 3: Pulled the codes on my code reader. It indicated rear passenger door lock actuator issue. Bingo. Reset the codes twice to make sure and within 24 hours the code showed up again. So had that replaced (about $550 for part and labour or $250 just for part and a v good YouTube video on how to do it yourself). A known and common issue.
BUT - next day I got the beep again... No codes now so that was a problem - just not the only one

Possible Fix 4: As also getting smartkey not found I wondered if car battery was too weak. It was 7 years old so decided to change it anyway to avoid other issues. Still got the beeps...

Possible Fix 5: Now there were no codes, beep was as soon as I pressed the door button (suggesting keyfob out of range) vs 2 seconds later (suggesting an actuator didn't work). Tried other keyfob and nothing at all - battery dead. So replaced the keyfob battery and it worked!! So as a last resort I changed the battery again in the main keyfob - with a branded battery and it was perfect

So - all resolved. Issue was one door lock actuator. And the keyfob battery. And the learning that my keyfob doesn't seem to show low battery warning - and a cheap non-branded new battery for it wasn't strong enough for the passive system to work reliably

So if you are replacing the keyfob battery get a good quality, new, known brand one. My new but cheap one just wasn't good enough
And hopefully the above diagnostic of many potential issues will be helpful to others...

 

wow man, appreciate the detailed write up. i have similar issue and very poor key fob range to boot. batteries are pretty fresh, lithium and name brand.. still does it. my question for you is what distance from vehicle can you make doors lock / unlock. I'm 10' at best and honestly usually have to walk back to within 5' of car to make key fob work. it's rare, but i do get the smart key not found message at times.

 

Hi Adam - my fob used to work about 5-10ft but since changing the battery (for the second time) it now works well at 20-25 feet. That's about all they are meant to work - it's a short range radio transmission

So - I would say find a different branded battery and give it a go to see if that helps...

Some have reported on here that the keyfob range seems to get worse over time - so maybe something about the electronics in the fob. Or perhaps like me they were using inferior batteries

 

mine was my passenger front door actuator... same issue.

 

I had a similar issue myself recently. Suddenly I was getting mislock double-beeps all the time. Started slow but soon became a constant nuisance. I tried battery reset, key fob battery replacement, I even pulled keyless module plug under the dashboard. Nothing worked. But I discovered that if I counted to 5 before pressing the lock button on the doors, the car locked perfectly without a sound. So I did that for an entire week. After 7 whole days, I decided to ditch the 5 second count and try to lock normally without waiting. It worked! Somehow that reset the system or something and I've never had a mislock since.

 

So - a hopefully final close to the double beep saga... it came back! Same again - intermittently double beep trying to lock, sometimes doors wouldn't unlock. But always worked if I press the keyfob buttons

A few months ago I had replaced the worn out buttons on the keyfob. I bought a shell on eBay to swap over the electronics and remember being disappointed that the silver bezel didn't fit well on my current case and the back of the new one was missing the jag logo. So I kept the old keyfob shell and just subbed over the new keypad.

Well - turns out it's a cheap Chinese import copy and the rubber keypad sits about 1mm higher than it should. Therefore the electronics behind it are also 1mm too far up and lose contact with the battery.

So - it always works when I push a button on the keyfob as I'm pushing the circuit board into the battery. On passive it works if the buttons are upwards and gravity is helping the electronics touch the battery. But not the other way up

Bought a new jag OEM replacement keypad and it has been 100pc since then

So - moral or the story. Don't skimp a few dollars for cheap copies of the key fob shell!

 

Brit, glad you got it worked out! I've had the same issue for years and have just learned to work around it, I will give fixing it a try now. Which reader are you using to get body codes?

 

one issue i had was that the driver side door lock itself wasnt fully locking. it was getting stuck mid-way, causing double beeps.


i sprayed some WD40, manually locked/unlocked by pushing/pulling the lock until it got all lubricated...fixed the issue

 

Which code reader are you using to get body module codes?

 

I use the iCarsoft LR II Land Rover/Jaguar Obd Scanner. On amazon for about $140 I think. Works well - gives generic obd read but also specific Jag and Land Rover code reading. Service light reset, parking brake service and some other features like that

Mine did have a sticking door lock actuator - the code reader logs that and tells you specifically which one. You can then clear that code individually and see if it comes back within a few days. In my case it did so I was sure that was part of the problem.

 

Sorry, I don't mean to hijack this thread but I have one more question. Do you know if it will read SRS and/ or ABS codes also?
EDIT: I went to Amazon to look for it, the ad says yes, it does have all that functionality. I'm getting one!

 

A few months ago on a warm Sunday afternoon, I was taking my family across town when the double beep started randomly occurring. I was quite baffled as to the cause because I have disabled the automatic door lock feature. It was only after about 5 minutes that I realised it also coincided most times with vehicles coming towards me in the opposite direction getting quite close.

Just as I was about to find a place to pull over and investigate, my daughter who was sitting on the back seat confessed to reaching out of the window and pressing the door lock button. Apparently the double beep reminded her of the road runner cartoon character so she wanted to say hi to everyone by using it!!

You don't find that one in the workshop manual.

 

That's hysterical!!

 

Where do you spray it?

 

I can't remember exactly what the behavior was, I think it was the double honk.

In my case the trunk wiring harness went and the car couldn't confirm the trunk was latched and would not lock.

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