I use adaptive cruise fairly frequently and unfortunately have learned to trust it and like it a lot (I know it’s a Marmite situation)…BUT tonight in stop/start traffic on M42, I got a shock….rolling along at about 10mph in “follow mode/queue assist”, (amber indicator illuminated on cluster) with cruise set to 50mph (grrrr, roadworks), just as my car was about to come to a complete halt, meters behind the stopped car in front, the system suddenly stopped “seeing” the car in front, so follow mode disengaged and the car started to accelerate up to the set 50mph. I caught it fortunately and cancelled cruise with a swift stomp on the brakes.
Ironically I was sat behind a lovely 23 plate L460 in pale grey. Stunning, but he nearly had my L405 embedded in his rear bumper!
The same thing happened several more times in the few miles of traffic whilst I was following him (obviously I was covering the brake constantly though).

I note the text in the manual on the topic of queue assist: The vehicle’s radar may not recognise a stationary vehicle as previously moving. In this case, it is possible that queue assist will not stop the vehicle behind the stationary vehicle. When approaching stationary vehicles, it is important that the driver is ready to intervene to avoid an impact, if necessary.

Very odd. No warnings (I have had warnings in past when cruise auto-disengages) and gives driver audible and visible alert when I’ve been in really heavy rain…but tonight was clear, dry, light and yet the £150k L460 a few meters from my front bumper “disappeared”. Be careful. L405 2017 TDV6 AB
Previous toys:
4.4 TDV8 Westminster. Santorini Black
1976 Lightweight
4.0l P38
2 Disco 3s
Lots of Jags. Confirmed JLR nut.

That's interesting. I had something similar a few times over the summer, where the car seemed not to 'see' vehicles with flat backs (HGVs and vans) in front of me, the yellow icon did not come on in the left side of the screen and the car did not slow down, it did however 'see' more complex, rounded etc vehicles, cars and motorcycles. At the time I wondered whether the radar 'eye' had been partly obscured by flies, but I have had it covered with snow so that the warning that it was inoperative came up on the screen, so if it had been obscured that ought really to have happened. It has not happened lately.

I asked the dealer to investigate at the current service, but as the car is sitting waiting for parts I expect it has not been done/won't exhibit the fault when tried by the dealer anyway. If any finding emerges I will post here. Only Range Rovers since 1988

Hi CS,

Thanks for your reply. That’s interesting, I had a similar thought regarding the profile of the back of the L460 I was following. As gorgeous as they are, the rear is a near vertical slab with very few changes in profile.
My car behaved normally a bit further along in traffic when I was following a more “curvy” Renault something.
I look forward to hearing what your dealer discovers and good luck getting your car sorted on your other issues. I had a two month wait for an air-con condensor last summer, due to JLR’s supply chain reconfiguration, so I understand your pain! L405 2017 TDV6 AB
Previous toys:
4.4 TDV8 Westminster. Santorini Black
1976 Lightweight
4.0l P38
2 Disco 3s
Lots of Jags. Confirmed JLR nut.

Perhaps LR secretly want us to 'mate' with a newer model to save them building as many baby RR's

On a serious note though, a tad worrying... i might set my adaptive to the biggest gap setting just to buy an extra second just in case (although I find that gap enough to let other roads users think they should just pull into it..!) Ash
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2016 SDV8 AB

Interesting! Never been brave enough to let it keep going when slowing down. I do like it for the most part, some level of trust is needed.

However on a dead straight local road, cruise set to 40 (the limit) as I approached some traffic lights it absolutely slammed on the anchors! Guy behind me almost went into the back of me…

Wish there was an option to flip to “dumb” cruise control !

Hi Jambo,

I've not tried it but I wonder if 'dumb' cruise control would be the case if you turned off the front radar - not sure if cruise works at all without it as havent tried it.

Its the radar that feeds the 'gap' setting so may not work at all without it. Ash
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2016 SDV8 AB

With ACC enabled, reducing the gap to minimum then again holding the reduce button for more than 3 seconds reportedly reverts to standard CC until the next ignition cycle on at least later L405s.

oooh - Didn't know that - Thanks Graeme  Ash
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2016 SDV8 AB

Amazing thanks Graeme!

I can confirm, I tested that today. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)