During a 12 days trip abroad, the car stayed in an open air parking lot at what we would call normal temperatures here (5°C to 25°C). When we came back, the car started normally, but all sorts of messages appeared: hill descent control disabled, ABS not available, drive with caution, etc. When switched into drive, it just started rolling and I almost couldn't brake! The pedal was incredibly hard to press! I stopped the car, waited, restarted it, same thing, impossible to drive. The parking owner came and asked what’s going on. He said that he used to own a Range Rover a few years ago and he found himself in a similar situation, in the middle of nowhere, without access to recovery so he called his dealer and the engineer reluctantly told him to disconnect the battery and to wait a minute, then to reconnect it... He said that this solved the problem, so he brought a wrench, we disconnected the battery and to my surprise it did solve the braking problem! Apparently a reset helps with this... I should mention that I tried to use the Autel OBD tool, but it couldn't erase the errors...

Last edited by adara on 2nd Jan 2023 7:43pm. Edited 2 times in total

Don't know much about the PHEV but that sounds like the 12v battery has died enough to cause multiple errors, not unusual at airports as all the electrical signals floating around can wake the car up multiple times a day, each time depleting the battery somewhat...

Battery disconnection and reset usually sorts it, just get the battery and 12v charging system checked out..  Pete
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2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
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Don't know much about the PHEV but that sounds like the 12v battery has died enough to cause multiple errors, not unusual at airports as all the electrical signals floating around can wake the car up multiple times a day, each time depleting the battery somewhat...

Another trip, another 10 days in which the car remained unused, this time in the garage, same behavior: no brake servo and the messages: OK to drive with caution, ABS not available, HDC not available.
But, disconnecting the battery didn't help this time... So I went to the dealer and they said both batteries need replacing, the 90 Ah one and the 14 Ah auxiliary one... Price at the dealership £330 and £240 respectively, without labour...
The price in specialized stores is £160 pounds (Varta, identical to the JLR labeled one) and £52 (Exide, also identical), available tomorrow. They reluctantly agreed to let me bring them, will see the fitting cost tomorrow & also if this solves the problem...

Last edited by adara on 2nd Jan 2023 7:44pm. Edited 2 times in total

Phew, the problem was solved. The batteries were indeed the cause and especially the auxiliary battery, completely gone, 0 volts... I would’ve imagined that the failure of a battery would generate start up problems, warning messages, but not braking failure!!! £245 for diag and replacement were added to the cost of the batteries...

Last edited by adara on 2nd Jan 2023 7:45pm. Edited 2 times in total

Interesting fault, I never really give the aux battery any thoughts. You would think the system would be clever enough to give you a warning

" Attention your Aux battery is failing this could result in Death, as your brakes fail!!!!"  2018 SE SDV8 4.4 Byron Blue

Precisely. There were no warnings of any kind, there were no starting problems, but it’s true that 99% of the time the car starts in electric mode (PHEV)…

I recently experienced a serious safety issue with my Range Rover and wanted to understand if it was just my car or something wider. After doing some digging, I’ve found multiple posts across forums describing exactly the same braking failure — this seems to be a widespread and very dangerous problem.

In my case, I was nearly killed in an accident. While trying to stop at traffic lights, I hit the brakes and the pedal pushed back into my foot. For 1–2 seconds, there was almost no braking. I ended up in the junction — almost hit broadside by a truck, with my wife and kids in the car.

An expert looked into the issue and confirmed it's a known design defect. Land Rover knows about it. It relates to the auxiliary battery — when that battery fails or voltage drops, it doesn’t trigger a proper warning, and in that state, it interferes with the system that switches from regenerative to hydraulic brakes. In those moments, the braking effectively fails.

I’ve been advised to report this to the DVSA (UK regulator) using this link:

https://www.gov.uk/vehicle-recalls-and-fau...ety-defect

— the process took less than 10 minutes.

In my case, the conclusion was clear: the car does not meet safety regulations in its current form. And it’s not the only JLR vehicle affected — the I-Pace had to be recalled globally for a very similar issue.

So if you’ve had even a single episode like this — please report it. It’s likely a matter of time before it happens again. All of these cars will eventually degrade, and the fault could return. Land Rover won’t act unless forced to — but if enough people report the issue, DVSA will force a recall and fix.

Please — it only takes 10 minutes. Report it. It could save someone’s life.

If anyone does report this in the UK or similar and get a response could you let me know?

That is a great idea and here is a link to the consumer safety gateway in the EU, for those living there and wishing to report:

https://webgate.ec.europa.eu/consumer-safety-gateway/