We have taken the new Defender on two long road trips. Both ways, we received error that adaptive cruise control and emergency breaking were no longer working.
no rain/snow, 50 degrees F outside, driving between 60-80MPH.

We were able to get it back on a few hours later in the drive. Or, we can turn it back on within a few minutes.
We confirmed exterior sensors weren’t blocked, etc. Anyone else having this issue?

 

Yup, had a similar message pop up a couple of days ago while I was driving, mine said Emergency Braking and Emergency Steering not available, which is kinda funny considering Emergency Steering is not an option in these cars to begin with... Sure enough, ACC stopped working as a result. Pulled over and checked the Land Rover oval, where the radar is hidden, to make sure it was clean and free of debris (it was squeaky clean), got back in the car and restarted the engine. Message was gone and ACC has been working fine since.

 

I received this same message several times at start up, whenever I was aired-down for off-road driving. I assumed it to mean that with less air in the tires, I could not expect as effective a response in an on-road emergency.

When I put air back in the tires it went away and did not return.

 

I haven't dealt with this on our D5... but our previous Lincoln had all the adaptive stuff and windshield camera... i finally figure out that if I drove aggressively shortly after start up or floored it out of the neighborhood causing any sort of traction control to kick in and didn't give it a couple if minutes to "wake up"... it would shut down all those doodads until a restart. I wonder if this is similar.

 

It's happened to me a couple times while off-roading, then it goes away once I restart the vehicle.

 

Happened to me as I left the dealership with the car the day I bought it. Had it back in the next day or so and they couldn't find any issues, yet then it happened to the service tech when he was bringing the car around to me. They asked if they could keep it to check it out further and it hasn't happened again. They said they installed a software update but I can't tell if that was done or not. However, I haven't had the warning return since.

 

I also get the Emergency Braking and Emergency Steering message on my Defender about 2-3 times a month. When I stop and restart the vehicle, the message goes away. If you don't restart the vehicle, I find that the warning goes away on it's own after an hour or so.
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2020 Defender 110 First Edition Indus Silver (Current)
2020 Discovery HSE Luxury Si6 Fuji White (Current)
2015 RRS Autobiography Fuji White (Former)
2011 RRS Supercharged Fuji White (Former)
2008 LR2 Fuji White (Former)

 

Has anyone checked to see if early aggressive drivining vs. Gentle early driving makes a difference? It took me months to figure that out on our Lincoln

 

The owners manual does not recommend early aggressive driving for the first 2,000 miles in the Defender. You are recommended to not fully press the accelerator pedal during this period, avoid high engine RPMs, avoid off-roading, etc.
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2020 Defender 110 First Edition Indus Silver (Current)
2020 Discovery HSE Luxury Si6 Fuji White (Current)
2015 RRS Autobiography Fuji White (Former)
2011 RRS Supercharged Fuji White (Former)
2008 LR2 Fuji White (Former)

 

By "early" i meant first mile or so of driving on each trip. With our Lincoln, if I was aggressive coming out of driveway or neighborhood directly after start up, all of my traction control and camera controlled adaptive cruise control and collision warnings would not set correctly and I'd have to shut down and restart. I had to learn to drive um, properly in my neighborhood lol.... was wondering if the rover was similar or this could be the causation.