Ok, so here is a couple questions/test.

1. If you unplug the battery, does it immediately "reset"? Or does it need to sit overnight?
2. What happens if you keep it connected to a battery charger overnight?

 

Echo-ing #2.

 

nope, disconnecting the battery has no effect on the reset period.

kept it on a charger for 2 days last week...didn’t make any difference, still had to use a key each day for the first unlock.

I swear, I believe it is some kind of lock function in the BCU.

it doesn’t make sense to me that it is a “lost” ground, or else it would be intermittent and erratic....but I’ve been looking.

could it be the under dash fuse box....again; it just seems irrational. If it were a symptom of that problem....why am I the only person (that I know of) in the history of the ownership of the model to have this problem.

is it the BCU....I think so; but I am not sold on the idea that it is a malfunction...I think it is a setting that can be edited.

but....I’m 54 years old, and I’ve been wrong before.

doc

 

These definitely seem to indicate it is intended function and not malfunction. I would attempt to narrow the window where the reset occurs. Assuming normal drive characteristics you likely let it sit overnight approximately 12-14 hrs. Start by cutting it in half and narrow the window on the reset time. So say 7 hrs in on normal reset time, approximately Midnight. Works? Yes/No. Then narrow each window in half steps. We need to know how many hours after first unlock and after last lock it occurs, so you need to do both test. Once you have last expiration window down to a narrow window, vary last lock time to see if that changes the window. Or is it the first unlock time? Sounds like there is a counter in the BCU that expires, we just don't know what starts it and when it expires.

I am with you, I think it is a security settting - obscure to be sure, but likely something you enabled when programming the key.

 

Soo I just found this ​​​​​​

TECHNICAL INFORMATION No: 86/01/01/NAS
KEYS FAIL TO UNLOCK VEHICLE AFTER SITTING OVERNIGHT
A vehicle parked in a radio-signal-rich environment with RF noise at or around the same frequency as remote plips – 315MHz – such as garage door openers, house alarms, gates in gated communities, or radio transmitters may exhibit the symptoms. Not all vehicles exhibit this condition. Low ambient temperatures can make the condition worse.

· Vehicle is within the VIN range YA260032 to 1A703319
· 1999 vehicles with 48K replacement BCU (YWC000010) OR replacement RF receiver (YWY100450L) fitted.
· Vehicle plips occasionally stop working after sitting overnight, or for an extended period.
· When mechanical key is used to unlock the driver’s door, plips start functioning correctly again.

 

Don't forget wifi signals too perhaps that didn't exist when that was written.

Sounds like you need an updated BCU?

 

There are no WIFI signals at 315mHz... But here is what a quick google brought up...

267 - 322 This band is allocated for exclusive Federal Government use. Operation of unlicensed Part 15 Devices is permitted between 285 and 322 MHz.

Could be the doc lives in an area with a military base?

 

Great find. Where did you find it btw?

I *really* would love an archive of all TSB's on these Disco's. All of them... Anyone know where or how?

(the last 2 issues w my truck were actually solved with TSBs and I spun my wheels for a good while until like this, I stumbled on)

 

I was just searching Google for various different combinations of words to try to find anything "land rover discovery 2 bcu sleep" the first result was the TSB on Landyzone.
​​
Kiss *** at a Landy dealer might get you access to the tsbs.

 

Or as stated in the doc other wireless (not Wi-Fi) car remotes/garage door openers/gated communities /etc

Pretty sure my HAM radio can listen to 315mhz and surrounding freqs.

Lots more spurious wireless emissions than when the trucks were built #5gdeathbeams lol