Jaguar Forum banner
1 - 15 of 15 Posts

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #1 ·
My car is occasionally refusing to unlock from the remote fob, when i press the key it flashes the indicators and i can hear the boot and fuel flap latches operate but none of the doors unlock and the mirrors dont unfold.Sometimes it unlocks on the second attempt and sometimes it takes 5 or 6 goes to unlock the doors.
Once in the car I press the start button and it may start first time or sometimes it just turns on the ignition and nothing else happens as if the brake pedal hadnt been pressed hard enough, although i know i am doing so as i can hear a whirring noise from an actuator under the dash when pedal is pressed but doesnt start.It then switches off and if repeated a few times the car eventually starts and is usually ok for the rest of the day.
I dont think it is a low battery fault as the stop start seems to work correctly within a mile or so of starting a journey which makes me think the battery is ok it also looks to be nearly new as does the auxillary battery..
Would a faulty door lock have these effects or water in junction box or elsewhere ?
So far it has always unlocked and started eventually but i am worried about getting stranded at sometime and want to resolve it as soon as i can.
I dont have a code reader yet but am intending on buying an i carsoft unit but dont know if it would be of any use with this issue.
Thanks in advance for any suggestions.
Paul.
 

·
Registered
Joined
·
2,198 Posts
No but i do have two keyfobs and spare has a new battery and does the same.
I suggest, as a first step, charge the battery. If you have an AGM battery, make sure the charger does that.
Secondly, suggest you buy a cheap multi-meter to check voltage of battery/batteries.
You could probably buy those 2 on Ebay for about £25 total.
AND Please tell us car model and year. :)

Paul.
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #5 ·
I suggest, as a first step, charge the battery. If you have an AGM battery, make sure the charger does that.
Secondly, suggest you buy a cheap multi-meter to check voltage of battery/batteries.
You could probably buy those 2 on Ebay for about £25 total.
AND Please tell us car model and year. :)

Paul.
I suggest, as a first step, charge the battery. If you have an AGM battery, make sure the charger does that.
Secondly, suggest you buy a cheap multi-meter to check voltage of battery/batteries.
You could probably buy those 2 on Ebay for about £25 total.
AND Please tell us car model and year. :)

Paul.
My car is a 2012 2.2 xf.
I did check battery voltage when I first got the car and was a little low due to the BMS module not being connected securely at the positive terminal.
I replaced that and went for a drive and then charging at about 13.5 to 14.5 v and 13v with engine off.
This morning it took 2 attempts to unlock but started first go, last night it took a few goes to start when I left work and the alarm light on dash kept flashing rapidly each time I tried. When I got home I had a look at the central fuse box and checked all plugs were seated correctly and it then started straight away as normal.I want to remove the washer pump plug to check for corrosion but not sure if that can be done safely with the battery connected? or should I let everything shut down and disconnect 30 minutes after switching off?
 

·
Registered
Joined
·
2,969 Posts
I've disconnected the plug in mine without allowing time for a system shutdown with no ill effects. Also check the lithium button cells in your remotes. A few of us have been caught out with fake batteries, the major brands seem to be subject to scrupulous Chinese (assumed) fakes which appear to give a good open circuit voltage but fail immediately in service. Try buying a well known brand from a trusted high street shop (not a pound store!). I junked a batch of 20 which were fakes.
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #7 ·
I've disconnected the plug in mine without allowing time for a system shutdown with no ill effects. Also check the lithium button cells in your remotes. A few of us have been caught out with fake batteries, the major brands seem to be subject to scrupulous Chinese (assumed) fakes which appear to give a good open circuit voltage but fail immediately in service. Try buying a well known brand from a trusted high street shop (not a pound store!). I junked a batch of 20 which were fakes.
I have not had a chance to change the keyfob battery's yet but the fault has changed, first thing in the morning or after having left it at work all day it takes two presses of the fob to unlock and the alarm blinker goes off, it then starts first time after a slight delay and the alarm light on top of dash lights continuously for maybe a minute and then flashes 4 flashes pauses and then 2 flashes repeating for a couple of minutes before going off .
If I drive for a bit then switch off and lock the car it takes 2 presses of the key to lock but will then unlock and start first time.
 

·
Registered
Joined
·
233 Posts
I'd suspect the main battery, the voltage is probably dropping too far under heavy load, assuming the terminals aren't loose ( check the bodywork end of the negative one too ), I'd suggest getting somewhere to test the CCA ( cold cranking amps ) of the battery with a proper load test.

I think the flash code with be 24 rather than 42, and as far as I understand 24 is equivalent to this code.
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #9 ·
I'd suspect the main battery, the voltage is probably dropping too far under heavy load, assuming the terminals aren't loose ( check the bodywork end of the negative one too ), I'd suggest getting somewhere to test the CCA ( cold cranking amps ) of the battery with a proper load test.

I think the flash code with be 24 rather than 42, and as far as I understand 24 is equivalent to this code.
Yes I think I will check in the boot at the weekend, as although not wet it does show signs of having been wet in the past.I will check battery voltage and earth points .
I think it is a possibility as both battery's look fairly new and the person I bought it off did say it had had a new small battery that cost more than the main battery to get replaced, so maybe there was an issue there,when I got the car the BMS lead was just hooked onto the battery terminal bolt at the +ve end and caused a charging fault to show when I disturbed it , I reattached securely and that corrected it.
It is just frustrating that the faults keep changing and I'm not fully confident in the car at the moment.It also seems difficult to find info on the alarm light code indication, I did buy a manual on DVD but it's not very well laid out and I have found no mention of the alarm fault codes yet.
I was going to buy an I car soft code reader but am now debating whether I should get a mongoose cable and SDD software instead , I do have knowledge of programming and can bus systems but in industry rather than cars but principles are much the same and would only use diagnostically not for programming unless essential.
Paul.
 

·
Registered
Joined
·
233 Posts
Yes I think I will check in the boot at the weekend, as although not wet it does show signs of having been wet in the past.I will check battery voltage and earth points .
I think it is a possibility as both battery's look fairly new and the person I bought it off did say it had had a new small battery that cost more than the main battery to get replaced, so maybe there was an issue there,when I got the car the BMS lead was just hooked onto the battery terminal bolt at the +ve end and caused a charging fault to show when I disturbed it , I reattached securely and that corrected it.
The posts on the battery should stick up slightly above or at least be level with the top of the part of the terminal that clamps them, the posts are tapered and it's a common mistake not to push the clamps on far enough before tightening them, then even when the bolts are over tightened to fully close the gap they don't clamp hard enough to prevent them working loose.
I'd be suspicious if the small battery cost more than the large one, perhaps they didn't use an AGM battery. Though maybe they just went to the mail dealer for the small one.
Personally I'm using ( on a 3.0d ) Exide EK151 for the small battery ( retails for ~£40 delivered, and Exide made the original jaguar battery ), and Exide EK950 ( retails for ~£127 )

It's not unknown to get a bad new battery either, so it's worth being cautious about pulling the car apart looking for a subtle wiring fault if you don't know for certain the battery is good.

The rear smart junction box is behind right hand trim inside the boot, so it's probably worth pulling that trim out and making sure it's dry, as all sorts of havoc can be caused with moisture in those.
 

·
Registered
Joined
·
8,892 Posts
...It also seems difficult to find info on the alarm light code indication, I did buy a manual on DVD but it's not very well laid out and I have found no mention of the alarm fault codes yet...
Here you go Paul:
Font Material property Parallel Number Pattern
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #12 ·
Thanks for that Pete, it appears to have been the 2 4 code idle message missing, that was showing up but today it took a couple of goes to unlock and then started first time.Yesterday I used my spare car as I didn't trust it but when I tried it yesterday morning it unlocked and then took 6 or more attempts before it started.
I have just put new battery's in both of my key fobs and will see what happens next, have checked both junction boxes and no sign of water in either of them .
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #13 ·
I changed both keyfob battery's for new Varta brand ones and sprayed both junction boxes with water repellent and the car now takes 2 attempts to unlock still but has started first go every time so far this week.
I have now got a code reader and will see if it shows anything on the locking system.
 

·
Registered
2012 xf 2.2 luxury.
Joined
·
15 Posts
Discussion Starter · #15 ·
Yes it's the drivers door,the indicators flash and I can hear the fuel flap and boot latch motors operate but the mirrors don't unfold and drivers door remains locked, second push unlocks just the drivers door as I have two stage locking set.
 
1 - 15 of 15 Posts
Top