2020 ES350 Battery Drain Issue
12-14-20, 09:48 PM
#76
Driver School Candidate
Started my lease on my 2020 ES 300h UL (not ES350, hopefully that's OK) in Feb 2020, before everything got locked down. Since then, I've only driven 3000 miles. Tuesday night, 12/8, I go to run some errands and the car wouldn't respond to the key. At first, I thought the fob battery was dead, but when I used the mechanical key to gain entry, no lights came on, nothing. My 12V battery was completely flat. It had been less than 48 hours since my last drive. The part that worries me about that so much is that the car gave absolutely zero advance warning that the battery was on the way out. No hard starting, nothing. I used my wife's car to jump start it and drove it around for 40 min. A few days later I took it in to the dealer and they ran a battery diagnostic. With no faulty cells found, they suggested I wasn't driving the car enough and that led to the flat battery. They actually suggested keeping it on a tender between drives. Not sure where these numbers come from but they also recommended driving at least 25 miles every other day. I keep the car garaged, car doors locked, and key fob in the house away from the car.
12-15-20, 12:54 AM
#77
Instructor
My 12V battery was completely flat. It had been less than 48 hours since my last drive. The part that worries me about that so much is that the car gave absolutely zero advance warning that the battery was on the way out. No hard starting, nothing. I used my wife's car to jump start it and drove it around for 40 min.
Last edited by ionian; 12-15-20 at 01:01 AM.
12-15-20, 08:22 AM
#78
Pole Position
A few days later I took it in to the dealer and they ran a battery diagnostic. With no faulty cells found, they suggested I wasn't driving the car enough and that led to the flat battery. They actually suggested keeping it on a tender between drives. Not sure where these numbers come from but they also recommended driving at least 25 miles every other day. I keep the car garaged, car doors locked, and key fob in the house away from the car.
). It has never been on a battery tender and battery failure has never been an issue. I understand what they are saying, and I understand the argument of a battery tender, especially on a standard 350 model), but I have never had an issue. It is my understanding that power from the drive battery starts the gas engine in Toyota's hybrid system, so the 12V battery really just activates a relay to start the car and runs the electronics, so it never comes under a heavy demand when starting the car like a conventional power train.The one difference between your car and my own is the fact that I keep it in a locked garage so I do not bother locking the car. I cannot help but wonder if locking the car turns on the receiver(s) in the car to listen for the proximity of the keyfob. Since that receiver doesn't need to be activated in an unlocked car, perhaps it doesn't draw as much energy? This is just a theory of my own and not founded in any inside knowledge. Perhaps someone on here knows whether there is anything to that theory?
Last edited by TechNut; 12-15-20 at 10:26 AM.
12-15-20, 08:37 AM
#79
Instructor
The one difference between your car and my own is the fact that I keep it in a locked garage so I do not bother locking the car. I cannot help but wonder if locking the car turns on the receiver(s) in the car to listen for the proximity of the keyfob. Since that receive doesn't need to be activated in an unlocked car, perhaps it doesn't draw as much energy? This is just a theory of my own and not founded in any inside knowledge. Perhaps someone on here knows whether there is anything to that theory?
12-15-20, 04:02 PM
#80
I have had the dead battery issue once, but never since. I have done two things that may have helped, though I don't know for sure. First, I keep the key fobs in the room farthest away from the garage where the car is parked, and I don't lock the car in the garage. I do believe that the car "connects" to the fobs if they are too close, which could drain the battery. I have also had the software update (the Enform update), and the dealer told me that update should also solve the battery drain issue. Not too sure about that one. Now if the dealer told me to keep a battery tender hooked up to the car battery all the time, I'd tell him I want my money back. That is ridiculous!
12-19-20, 09:19 AM
#81
Driver School Candidate
The one difference between your car and my own is the fact that I keep it in a locked garage so I do not bother locking the car. I cannot help but wonder if locking the car turns on the receiver(s) in the car to listen for the proximity of the keyfob. Since that receiver doesn't need to be activated in an unlocked car, perhaps it doesn't draw as much energy? This is just a theory of my own and not founded in any inside knowledge. Perhaps someone on here knows whether there is anything to that theory?
12-19-20, 10:19 AM
#82
Pole Position
Such an interesting theory. The reason I originally mentioned keeping the car locked in the garage was based on experience with a circa 2011 Jaguar XJL. Those cars had a very well described battery drain issue that was specifically tied to leaving the car unlocked in the garage, for example. Apparently as long as the doors remain unlocked, the car never entered the most powered-down state which would drain the battery fairly quickly. Seems like a possibility that the reverse could be happening here if your theory is correct.
03-01-21, 04:51 PM
#84
Closing Thread ??
Searching "dead battery" certainly helped me...which is WHAT THIS FORUM IS FOR... at least NOW I have something to go on when I call the stealership tomorrow!!
04-14-21, 12:49 PM
#85
Driver School Candidate
Join Date: Apr 2021
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More than a few people have posted about the 2020 model having a dead battery after a few weeks of sitting. The thought is that this model has some sort of issue that's drawing the battery down. Not an issue with previous years. Please post if you've experienced this and if your dealer found a fix and what that fix is.
04-15-21, 11:28 AM
#86
Fixed the problem
We took our car to the dealer on 3/2/21 and they already knew about the issue with the dead batteries in the 2020s... service writer said there is a TSB specifically about the issue... and it involves a simple software update.... had our car back to us in 2 hours... and we have not had the problem since... hopefully.... we will not have it anymore
04-27-21, 04:46 AM
#87
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New guy here.....went searching various forums when our 2020 ES350 exhibited the dead battery issue the day before yesterday. Had roadside assistance (AAA) tow my car to the dealership yesterday (we jumped it in the garage and drove it up the flatbed). By the time we got to the dealership, we had to jump it again to get it off.
I explained that this might be a known issue on these cars to the rep, who claimed not have heard of this problem before. He mentioned to the tech as he handed over the paperwork to go ahead and swap out the battery, as the car is so new (I figured "good"). They called me a a half hour later saying they would need to attempt a charge first, which is what they were doing. After returning to the dealership, I was told the it is charged, but that there is a software updated needed and the car would need to stay overnight (it was late in the day). I asked how the software update might have affected the battery, and was not given a straight answer. I am going to dig some more today when I pick up the car. Anyway, it kind of ties in to some of the previous posts.
I explained that this might be a known issue on these cars to the rep, who claimed not have heard of this problem before. He mentioned to the tech as he handed over the paperwork to go ahead and swap out the battery, as the car is so new (I figured "good"). They called me a a half hour later saying they would need to attempt a charge first, which is what they were doing. After returning to the dealership, I was told the it is charged, but that there is a software updated needed and the car would need to stay overnight (it was late in the day). I asked how the software update might have affected the battery, and was not given a straight answer. I am going to dig some more today when I pick up the car. Anyway, it kind of ties in to some of the previous posts.
04-27-21, 06:45 AM
#88
Instructor
Take a look at the below video. This guy is a master tech specializing in Toyota. Skip to around 12:51. He is talking about common complaints with battery dying prematurely. Our Lexus vehicle works on same tech:
Last edited by ionian; 04-27-21 at 06:46 AM. Reason: ...
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07-27-21, 02:37 PM
#89
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Battery dead
Car wouldn’t start Monday - last used Friday. AAA came Tuesday and charged the battery. Said battery was fully drained. Brought to Lexus service.
So the problem isn’t the battery. It is a software issue. There is an “evap” check done via the computer every day and the software issue is this automatic check gets stuck and keeps going which then drains the battery. Just need to have the software updates!
So the problem isn’t the battery. It is a software issue. There is an “evap” check done via the computer every day and the software issue is this automatic check gets stuck and keeps going which then drains the battery. Just need to have the software updates!
07-29-21, 04:41 PM
#90
Pole Position
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