wrinkle

I agree. Lexus is making me quite regret not even considering a BMW PHEV. Given how the latter's reputation for reliability has risen in the Consumer Reports reviews - in hindsight, I shouldn't have so ignored the NX450h+ sightings of this ridiculous 12 V battery management design in this forum, which I then considered something as only affecting folks in very cold climate. The primary non-negotiable reason I chose Lexus was reliability.

If a bigger sized battery or Lexus firmware update doesn't fix this, I may not choose to stay with Lexus long-term.

LeX2K

If this was my vehicle I'd something like this

wrinkle

It doesn't fix the problem - and wastes my money and time, as far as I'm concerned. So I'll pass being a "Lexus Champion"

RBach

Thank you very much for sharing what the dealer service dept told you, about changing a DCM. I truly hope that resolves it.

Yes, I sure will pass along that you had the same issue(s), and that is what they found. Fingers crossed this builds the Lexus engineering database, to create a quicker solution for those to come. Then on vehicles in production, changes the process to prevent from recurring for others.

Blessings

Rich

alextv

This gets back to the extensive tests that were done on your car. Find out from them what the cumulative parasitic draw that they measured and what does Lexus deem as normal draw. Not sure if you have done this but you can put an ammeter in series with the battery and see the spikes that happen quite often by the DCM transmitting. Just make sure your key is far away and put scale on 20A for initial spike and then reduce to ma scale. Mine jumps from 75 to around 200ma. If all seems to be in normal range then the battery is probably weak even if it checks ok but I think you have said the battery has already been changed. There will most likely be a software update to address the issue and no one knows they are working on the fix until it happens. Knowing what the draw was during there tests is important and not just the voltage drop.

CommodoreAmiga

I'd be curious to hear what the official threshold for vampire drain is from Lexus... But 75mA already sounds too high. I think other manufacturers specify upper limits around 50mA and actual drain is often much lower -- 10-15mA.

RPerez13

Did you have to purchase an extension cable to connect to the Neg Terminal in the hood (not back of car)?

wrinkle

I measured the resting voltage 4 days after my 40 A-h nanny charge to the battery - its at 11.99 Volts.

I'm thinking I will let the battery die again and then haul the car to Lexus dealer and ask for a replacement battery. And ask for the vigorous document, of course. If that's the game Lexus would like to play, so be it.

alextv

So full charge and after sitting not driven and 4 days at 11.99V. At that rate doesn't sound like it would last a week. These cars are in such short supply that you couldn't even test one on the lot because they are not there. Something is not right.

wrinkle

No, not sitting for 4 days - driven 45 miles during those 4 days

alextv

Ok so charging some and comes down that low after 4 days. Sounds like excessive drain or software needs to change charging parameters. But to give you an example my 2020 ES300h measured yesterday at 12.22 and today at 12.2 so very little drop. Did a full charge 10 days ago. My drastic drop in drain happened when the trial subscriptions ran out so the constant transmission from DCM is the problem.

wrinkle

I don't know if its excessive drain - I have turned off all the "Car-alerts" paraphernalia that SMartin in the other thread advised, including digital key. Unless there is a hardware/DCM that is bad, I'm not suspecting those car alerts to be causing the problem (since SMartin claimed he measured the current draw before and after he turned off these app/car settings, which led to a ~300 mA quiescent current draw to 28 mA for him, I believe).

So yes, it could be hardware module that is rogue - or it could very well be exactly what happened to SMartin - because of Lexus' idiotic 12 V charging design, the 12 V battery degraded to the point where it needs replacement because it won't hold charge.

(I'm almost wishing this had started earlier in my ownership, like 1st week, for me as well - so that I could've triggered a Lemon Law return like others are planning - Lexus will only pay attention when it hits the pocket book, hard. Or a lot of talk about it in the press, consumer reports, JD power etc. If it doesn't cost Lexus money and business, they won't care)

pcm888usa

Lemon Law in California does not have time limit. If the same problem occurred 4 or more times or the vehicle spent over 30 days in the shop, Lemon law kicks. I registered complaint with Lexus ahead of time because my car was less than 1 month old when the problem occurs. I am hoping Lexus could honor a buy back as good faith. Is not, Lemon Law meter is running.

alextv

My son purchased a Ford truck here in NC that was a Ford buyback in California because of lemon law. We were told that in California you basically can turn the vehicle back in just by handing the keys back without any repercussions. Sure it is not that easy but a lot easier than here in NC.

wrinkle

I suppose you mean that you registered complaint with Lexus corporate (not just with dealer) ? How did you do that ?