So this is what could be happening...... If you turn off your car before you put it in Park and then put it in park, the car seems to be OFF, but the lights are still on. Even though you lock the car (it doesn't matter if with the fob or the button) the lights will stay on. So maybe ask your wife if she accidentally turns off the car before putting it in park?

Interesting that the lights would not go off in this case. At any rate, I checked and the lights were in auto and she drove to work in broad daylight. So there's no chance that the lights were on when she parked.

It's remotely possible there is a fan relay not shutting off until power dies. But if Lexus has checked the car, they would have found this pretty easily.

I'm leaning toward some kind of relay sticking and causing the drain. Since this only happened twice in about 10 days, it is intermittent. Lexus would only see it if it happened to occur during their test. I'm still puzzled that the doors were unlocked.

Sounds more like a shorted cell in the battery to me.

That was my first suspicion. But, Lexus swears that is not the case. They load tested the battery in multiple tests.

After we let the car run for 10minutes, he tested the battery--turned out the battery cold crank amps were lower (400) than the recommenced 500+ for our car.

Went out and replaced the battery (80bucks)--Seems like it starts up fine now.

I don't think 10 minutes is enough for the alternator to get the battery up to capacity. I've read 20-30 minutes is required. But, if replacing the battery would fix this, I would be happy to do so. Convincing Lexus to do that is a challenge since they say the battery is fine. So, it would have to be on my dime. And, if they're right, then my dime was wasted.

Thanks, everyone, for your feedback on this. I think I'm going to continue driving the car myself for the next several weeks and try to emulate what my wife did in hopes that it drains again. When it does, I plan to insist that it be towed to Lexus while dead (instead of jumping the battery). Maybe having the car in that state will help their troubleshooting.

 

Just had the battery replaced. In warrantee.

I saw the bill to Lexus: $177.00.

Battery dead. Jump started. No more problem for a while. Then........battery dead. Over the last year the car wouldn't start on 4 different occasions.

Also Lexus states its normal for the check engine light to come on when the engine turns over too slowly when trying to start. The light came on.

The replacement battery is a 84 month Lexus battery.

 

Never got the check engine light. Also, with mine, the very curious part is that the doors were not locked either time the battery was dead. I know she locks the car after getting out. I don't think it unlocks while the battery is dying. So, that leads me to conclude that the car never locked.

Based on everything I know so far, this has to be it!!! No, the lights weren't on. BUT, the ignition stays on AND the doors don't lock (big clue here). There are a couple of beeps that happen as you exit the car. But a noisy parking lot could overpower that. I asked her if this was POSSIBLE. She agreed it could be. BTW, in that state (button pushed off with car in gear), the key fob does not operate (hence doors wouldn't lock). But, both trunk buttons do work (on dash and on trunk lid).

 

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So this is what could be happening...... If you turn off your car before you put it in Park and then put it in park, the car seems to be OFF, but the lights are still on. Even though you lock the car (it doesn't matter if with the fob or the button) the lights will stay on. So maybe ask your wife if she accidentally turns off the car before putting it in park?

Interesting that the lights would not go off in this case. At any rate, I checked and the lights were in auto and she drove to work in broad daylight. So there's no chance that the lights were on when she parked.

What I mean by this was the driving lights.....................

 

A definite possibility!!

 

I have very similar problem, have you found a fix?



here is my thread for anyone who can help:

https://www.clublexus.com/forums/is-...ml#post5299712