2006 LR3 89k miles

I was getting the HDC fault before cold weather start up. I park on a hill nose up so I thought is was just a phantom error because it all cleared and everything worked fine.

Then I got the suspension fault while waiting in the drive though at Mickey Ds (dont judge me) Drove home no issues.

There's three new trim levels of Big mac BTW

Next day during a snowstorm the truck loses it. Drops every code, ones I've never seen. Goes into gear limiting drive mode.
I stop, it shuts off. Will not restart. eventually restarts in some sort of low power safe mode. I call for a flat bed.

I have a great Indy LR tech here in Reno, NV and he replaces the alternator. Checks the battery says its good, thats lucky because he says the also battery goes when that happens.

Turns out I had a failing alternator that was tripping up the HDC because that the first computer in line. The alternator was over charging and the truck shut down to protect other computers. Tech says it a common issue at 90k

All cleared up and running awesome again.
I will keep an eye on the battery with a cold meter.



Just wanted to add this into the mix
Because I should have checked the charge system when the original HDC faults turned up

 

Good post. To put some numerical data with your findings, cars start freaking out when voltage drops below 10.5-11.0 V and when voltage exceeds 15.5-16.0 V. When on-board computers stop communicating, errors start popping up. I don't think it is so much that HDC is "first in line", but rather its dependency on so many other systems.
Glad you got it fixed!

 

Yes good post....had a problem statement, a resolution, a happy ending, some information...and even some humor. My alternator went **** around 90k Miles as well, although it howled at me before causing faults. Had you noticed any squealing kinda like a loose belt sound?

 

When my alternator died I could smell the lovely aroma of burnt electronics from it. Apparently when it went to charge my battery it couldn't handle the load and poof it went.