Daft question, but first time doing anything myself. I need to disconnect by battery for 30 seconds to reset my handbrake after changing my pads. Could someone point out what to disconnect?

 

You shouldn't need to disconnect battery. You just calibrate the parking brake. From memory I think you put the car in P. Press foot brake 4-5 times to adjust the pads to the new discs. Then apply the parking brake on then off a couple of times. I believe that recalibrates it

 

For some reason which I have yet to understand at all, battery disconnect on these cars is not as simple as the good ole days when you just removed cables from posts and did what you needed to do. I disconnected mine a while back to simply replace the battery like I've done a hundred times in my life......and ended up spending $5000 at the dealer to get the car back to life. It blew out keyfob recognition, the main cluster, an entire fuse box and misc other stuff. Now, I am petrified to touch that battery. I actually paid Jaguar dealer to do a simple battery replacement a few months ago. Guess what that cost.

 

Disconnecting the battery, changing it and reconnecting does not blow anything up
The brains of the car got scrambled because a battery disconnect procedure wasn’t followed
All the modules you mention can be reprogrammed to work as they should via sdd

 

So what’s the proper procedure?

 

Open the boot
Go away for twenty minutes to wait for the systems to go to sleep
Don’t bring your keys anywhere remotely close to the car - 5m at least
When you come back, don’t open any doors. This will wake it up
Change the battery as normal
Alternatively, you can buy devices which plug into the obd port which will supply a voltage (small 12v battery) to the systems while the battery is changed

 

uhhh....the Jaguar dealer could not reprogram it.......that dealer told me that on that car, it MUST be tethered to a life support power supply before battery disconnect or it will lose all comms. So, stupid me, I disconnected negative cable, disconnected positive cable, lifted battery out, dropped new one in, reconnected positive, reconnected negative, lost everything. Towed to dealer where they decided I needed all of the mentioned components and even still.....they were unable to re-establish communication between new smart keys and the docking port, even after consultation with Jaguar corporate technicians. They said they simply have no resolution so I took the car without docking port recognition....I don't believe the owners manual on a 2009 XF tells you to tether the car to a power supply before disconnecting the battery.

 

Where in the owners manual of a 2009 xf does this battery procedure appear.? It's not in mine.

 

I’ve got a 2014 and it doesn’t say any of that either in my handbook
it says to take it to qualified personnel
the cynic in me says no surprise there then, just another way to fleece you of more cash
but….
trust me, that above is how to change a battery on these things
that is, up until, I think, 2015 when it got easier

 

Well I've self maintained my own vehicles including boats for 50 years and I never had anything like the event I described happen before. I still own the car, but I will not ever disconnect that battery again, and I won't let any other indy mechanic do it either. To the extent that I just changed out the fuel rail assembly on it and contrary to the Jaguar service manual, I did not disconnect the battery for this job. I was just really really cautious with any dripped fuel.

 

I’ve disconnected the battery twice in the last couple months. Swapping out the seats, I didn’t want to risk the airbags and pre tensioners doing bad things. I guess I’ve been lucky to not scramble its brains.

 

It depends on the year of the car
I think the pre-facelifts were ok and after 2015 were ok, but don’t quote me…

 

All I can say is this 2009 XF is a pretty car and fun to drive, but it definitely scrambles my brain.

 

I will post this TSB again. We have a very unique and localized problem that so far has ONLY showed up on 2013-2015 XF's. IF your car is in that range be VERY aware of what I am going to post. Look up thread and see where it cost thousands of dollars when an owner attempted to change the battery.

The TSB only mentions that the locking/unlocking stop working but we know now that it also extends to the car not seeing the smart key and then your unable to start the car.
Note there are 2 ways to fix this so far.
Jaguars way which is the replacement of at least two junction boxes (Fuse Blocks to us old guys!). Costs are $3000-$7000! Plus there is no guarantee that it won't happen again next battery change. Jaguar has not released any information on why this happening BUT they do know what the outcome is.

Second way is using an Autel device that can reset the errors and get the system/car working again WITHOUT replacing these expensive junction boxes. The downside to this way is we never got any info on exactly which Autel device to use?? The other downside is this does not fix anything. So the next time the battery is disconnected your back to square one and need to fix it all over again using the unknown Autel device.

Can anyone post which Autel device can reset these errors?
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I’m not 100% Autel aware but I have played with the ones at my last job (service writer/parts counter) and the new one at my current job (boat repair/Stereo installation). I was looking at the newest one for the last guy I worked for. The big deal with the newest bestest one is an ability to see into each module on the CAN Bus.

I have not looked into getting an SDD set up. My previous boss had no problem buying a cracked one from Russia but my understanding is that you’re equally likely to brick the car if you’re not careful.

 

Yes Autel has some very sophisticated scanner tools but there are just so many models I was not sure which one would do what we need?
I did not mention SDD because the dealers have been replacing the junction boxes as per the TSB I posted.
So that tells me SDD can't just reset them but I am not sure?

Really wish we could get a full description of what's happening too? Still shooting in the dark!
I do know the junction boxes have a lot more stuff in them then fuses and relays so something is getting damaged in them.
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Sir, what you describe above is exactly what happened to me but mine is a 2009 !....here again is a recap of my experience. The car battery went dead and needed replacement. So I went to Auto Zone and bought a battery like I've done a hundred times in my life. Disconnected the cables and dropped in new battery. Instantly displayed smart key not recognized. There is a local indy mechanic who specializes in Jags and he told me he could reprogram it so I towed it over there. Later in the day he notified me he was unable to establish communication and did not know why. Towed to an official Jaguar dealer/service center where I was told I needed a "fuse" junction box, two new smart keys, the cluster because it apparently cooked the anti theft thingy and other stuff I can't recall. My bill was $5,000 just to get the car to where it would start again and even then, the dealer was unable to reestablish communication between new smart keys and the docking port. They spent a week on phone with Jaguar technical support and eventually told me that neither they, not Jaguar technical support could figure out why the docking port would not reestablish connection. So I took it the way it is and do not have use of docking port if ever needed. Since then, I took the car to the Jaguar dealer for battery replacement because my logic is....if they disconnect the battery and blow everything up, at least I may be able to hold them accountable. Scary.

 

Sorry to hear of such an expensive problem! But good info since you have a car outside the 2013-2015 range the TSB mentions.
Thanks for reporting back.

I just want to find out what is happening? All of Jaguar products share a lot of electronics so it's a bit odd that ONLY certain year XF's have this issue?
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Dealing with some of this myself at the moment and it sort of seems like the <2012 cars had some electrical problems, which they attempted to resolve, but actually made worse in the 2012 > 2015 cars...