ABS Sensor

Has anyone else had a failed rear ABS sensor?

I have had an intermittent issues with the LR4 basically becoming useless.
No ABS, TC, DSC, TR, and suspension sitting on bump stops.

At first I was told is was the battery by the dealer. It was replaced less than a year ago, so it was replaced again under warranty.
Everything was great, until 2 weeks ago, when I got a repeat of the failure multiple times.
Sucks be out and about with the family while on the bump stops.
When I pulled the codes I kept getting the same "Left Rear ABS Sensor erratic signal" fault.
I passed this information along to the dealer, including the log from my IID tool showing the 0 speed indication the Left Rear Sensor.
They insisted it was the alternator not charging the battery, causing weird signals from the sensors. If that was the case, why am I not getting weird signals from all of the ABS sensors or any other sensor for that matter. I was an ASE Certified Technician with JLR (Woburn Jaguar, and Land Rover of Peabody MA) for over 6 years, none of their conclusions made any sense. But it is the winter and I just don't have time to properly diagnose my own vehicle. They assured me they had done a current draw test on the alternator and it was weak but not INOP. So this COULD cause an intermittent failure, or could not charging the battery all the time. Yeah sorry thats not how an alternator works on our LR4. Because of the way the computer balances the battery and alternator depending on the load requirements and the need to extend the battery life if possible, a "weak" alternator would not even show up. Either it would be dead, or no issue at all.

Given how easy it is to change the rear ABS sensors, I ordered one. Hopefully it will be here tomorrow (with our 2' of snow coming down today...).
I'd rather try a $40 dollar solution and fail. Than a $1000 solution from the dealer, which I know is wrong.

It couldn't be a faulty brake light switch, could it? The symptoms were pretty much those you described in the LR3 when that switch would fail (or an incorrect type of brake lamp was used to replace the original one...) Anyway, that would be another inexpensive part to try and replace, if your ABS sensor doesn't fix it.

I've done the brake light switch when this whole thing started to happen about 1.5 months ago

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I have the same issue, with the exception that it says it's the right rear ABS sensor, started 10 days ago. As background I have a 11 LR4 with 78K miles on it. (And a 99 disco that never seems to not have a problem but that's for another day) I have an AutoEngunitity pro scan with the Land Rover package and it's pulling a C003a code. I replaced both rear ABS sensors because I figured if one failed the other had to be right behind it. That did not fix it. I read a lot of posts from LR3 drivers about brake switches so I rolled the dice on that with no luck. By the way the brake switch is a Ford part and if you don't have a LR dealer close you can get it from them. Finally I decided that it might be battery or alternator. I put my multi meter on the battery and got 12+ volts turned off and over 14 volts while running. Then I put my battery charger on and it showed 50% charged with the ignition off. I left it on for a few hours took it off and started the LR. All of the warnings went away and I thought I had it sorted, old battery. So I went and got a new one installed it and then I let it idle for 5 minutes and the warnings came back. So I turned it off, hooked the charger back up and fired it up again. No warnings, pulled the plug on the charger and warnings came back. I'm ordering an alternator tomorrow and hope to have it for the weekend for what looks like an easy install which my gut says will suck. I'll update with results once I have some.

Replaced the alternator and all is right in my world again.