Mine (2016) is a dual-cell battery and I think later went to single. The dual is one permanent, one rechargeable. As noted above, I recall it taking an hour or so of driving to top it up after initial installation. Recently I've had the "SOS unavailable" message again when it's been two weeks or more since driving, but it still recovers after even 20-30 minutes of driving.

 

for sure! there's enough of us with this issue. Would be nice if it was just a 'new' battery that failed to charge and finally died.

As much as the less expensive/Amazon ones are...going the factory part would be best. especially if you have vendor ghosting as mentioned above.

It may be that I spent $72 on a battery that didn't solve the problem, hoping it does.

 

MIne was a genuine JLR one for £21.43 delivered, back in July 2024 from British Parts.

 

yes, I'm sure it was. 2 years ago and no tariffs. I bought the JLR chrome and black bonnet vent upgrades for @$60 each back then. Now they're over $200 and that's ON SALE.
https://jaguar.oempartsonline.com/oe...456?origin=pla

 

Friday April 10 update. Got to the TCU battery project today. This time I had the deepwell 10mm socket. Got the August 2025 battery out and this new one, Jaguar stamped as well as date stamped, Went in fine. Got the car outside for a drive and pressed and held the left overhead test button. Did its rapid flash, then its slow flash and I released the button. This time the button stopped flashing and TURNED BLUE, This color change had NOT happened before. With much hope I brought up the app and unfortunately, it still showed the car in its December location, asleep and driving.
Very discouraged at this point, but still have my JLR Tech appointment this coming Tuesday. He told me not to worry, we'd get it figured out. Stay tuned, I'm still hopeful.

 

Ok I had to look that up as I didn't know what the blue meant. Apparently it's showing the car ready to make a call out or after completing. Attached the relevant section of the WSM doc for it, as I learned something today!

 

Appreciate the link, but as JLR mgmt. do tell us what is going on with our Fs that seemingly no longer want to play nice with the Remote and protect app? Jaguar indicated early on... 2020-2022, that they were going to support the Remote and Protect functions! lock, unlock, track/trace the car, etc. JLR sold me the subscription and it worked until mid December 2025.

Honesty sells cars!!!!

 

No idea, the telematics stuff is handled by an outside company. I'm just a local technical guy, I don't get good info on that level of decisions beyond what they tell everyone. I will see what I can dig up during the week though.

 

Many of us will be hopeful that you can uncover some help.

Took the F in today. On the way, I did the soft reset, pressing the left wrench button, holding it until the fast flash became slow flash. This time NO blue button.

Are there any plans for 3G/4G TCU replacement units?

 

According to what I know, the early TCUs are no longer produced by the manufacturer, and there is no plans for future replacements once stock is gone. The earlier cars we are coding out the TCU to allow the car to work without it if failed, as there won't be a replacement part available. The later TCUs are still the same as what's being used in new cars, so they will be supported for some time into the future.

 

Sad to say, as much as I love my F, I am REALLY disappointed in Jaguar. First they don't offer any Nav updates in the US for 2017s and older.. cars that require the USB input, not SD card. My nav still works, but maybe that's going to vanish as well. Second, I found out from my tech who is currently working on my car, that NO, NO updates, NO upgrades, no nothing.

"The official answer is there is no fix. I tried everything on my end to wake the module up but it does seem to be that all of them are offline and no longer supported. I called and spoke with some higher-ups about it; they said there was talk of a retro fit however they have abandoned it. I am not sure reading your article if that would work the guys at JLR said the programming wouldnt work, there is a lot of background stuff is what they told me, not sure what to make of it but I am so sorry! They gave me this form for you to fill out to inform you of the features going to be disabled "

He attached a copy of the PDF that has to be filled out for the service to be disengaged from the car (and refund me the balance of my Remote subscription) That PDF is here.

What I/we can hope for is that some entreprising soul will figure out a workaround for this and will come up with a brilliant and affordable solution.

RoverJoe, thank you, as well, for taking your time to look in to this on your end, much appreciated!