Dead battery issue

[William T. Miller]

As described in more detail in the attachment, I own a Lexus US250h, which I purchased in September 2020.  Since that time the battery has not started on three separate occasions (Oct. 2020, May 2021, and November 2020).  I have had to have the car jump-started each time, after which I drove it to the Lexus dealer and recited the problem, each time with more passion as I realized I was sold a defective car.  Each time Lexus ran certain diagnostic tests and declared the battery to be fine; most recently it did a leak detection analysis which showed nothing.  The Lexus position, despite the facts of three successive battery failures within 14 months of purchase, is that if the diagnostic tests do not show a problem, then the problem is the owner!  In the most recent visit the advice to me was to drive the car more (despite the fact that I had informed them that I drive the car daily, both in town and on the road) and/or to buy a "trickle charger," to which I responded I did not pay $40,000 for a car to be told I needed to purchase and use a battery charger.  The responsibility is Lexus's to provide a reliable car that starts each and every time the ignition button is pushed.  In short, the car is a classic lemon, and I have filed a complaint letter (see attached) to begin the process of getting relief.   I have been told that other UX owners are experiencing similar problems; if that is true, kindly share your stories. Thank you. 

Letter to Lexus re UX250h.docx

[Cambridgehank]

Did you get a reply?  Was this issue resolved?  

[William T. Miller]

The only response from Lexus, regarding a recurring dead battery issue on my Lexus UX (4 dead batteries in 18 months), is that I do not have a problem!!!  Hence, it will do nothing. 

[Cambridgehank]

This is our first Lexus.  I thought their customer service would be better than others.  Wrong on my part.

[Jenny Kelly]

I am having this same issue. I purchased mine in Feb 2021 and it wont start in Sept 2021 and had to be towed to Lexus. They replaced the battery.  Happened again today. Currently waiting for someone to come tow it to Lexus again. So frustrating.

[RX400h]

How often and how many miles do you drive per trip?  If your trips are not long enough, what you describe is not surprising.

[CA_SKR]

I have 2020 UX 250h and it has happened to be 3 times so far and every time i had to jumpstart or manually charge the 12v batter. This is ridiculous. Why lexus has not paid any attention to this problem?

[RX400h]

If the dealership cannot figure it out, take it to an Auto Electric Shop. They specialize in solving electrical issues that lead to battery drain.
Here's an example of one that is in my area:

Welcome to Pacific Auto Electric | Best Car Repair Shop | Poway

When dealerships are stumped, these guys always come through.

[Bykfixer]

Often times when parasitic drain is ruled out it turns out that it's a ground wire issue. Spotty connection at the contact point to the car or sometimes the wire itself at the connector. Being spotty, it shows up unexpectedly. 

Many expect a check engine light to light up but if it doesn't affect emissions the light does not light up.

When my brother kept complaining about his battery being dead at random times he eventually figured out he wasn't running the engine long enough to recharge the battery so after a few weeks his battery would not have enough juice to start the engine. He began driving on the interstate for 30 minutes at 3000+ rpm's once a week and the issue ceased. 

All of the computer stuff in the modern automobile takes a lot of power to run them. Combine that with alternators not much more  powerful than it takes to keep all of that stuff going and you end up having dead batteries at odd times because instead of recharging the battery in 15 minutes like before it now takes 30-45 to put back the juice it took to crank the engine. It takes a lot of electricity all at once to run the starter motor to crank the engine. 

Most "technicians" at dealerships anymore paint by numbers when it comes to fixing problems. If the book doesn't spell it out they are stumped. If the book left out a detail they have no clue. Oh, they'll charge you a fee and say they fixed it but many times they have not. It's sad that cars have gotten so complicated it takes a book with step by step instructions in order to make common repairs. A Lexus is a fancy Toyota, so you find a local repair shop that fixes numerous brands and you'll most likely get a correct diagnosis. 
 

 

[yumseyo]

Great Post's !  I just bought a 2020 UX 250h in Aug and have been driving it every other week when I switch it out with my 2013 ES300h. The UX started fine until I skipped 1 week and the UX sat for 2 weeks and I couldn't start it !!  I jumped it and took it to the dealer and they said "I don't drive it enough and I need to get a battery tender (trickle charger)".  I know the technology is much different in the UX vs the older ES, both hybrids...but two weeks is a little light.... The UX sits outside and having an extension cord go out to it is a pain and when the neighbors ask...."whats up with your NEW Lexus !!"

[Johnney]

Can the batteries be swapped from the nickel metal hydride to ion lithium hydride?

[Fredwoire]

Run for the hills - 2019 UXh battery died Feb 2020 and March 2023. Parked 4 days in a garage before each event. Dealer said vehicle needs to be driven more ??? If a purchaser knew of this prior to purchase another vehicle would be in my garage. Have extended warranty and dealer charges for diagnosis etx ! Crazy ! 

[RX400h]

Much depends on the length of the drive when you take the vehicle out. With ANY ICE or hybrid vehicle, if you drive 5 miles to go to a store or other destination, then drive home, the alternator may not be charging the battery sufficiently.

Whenever I take any of our vehicles out, and my destination is a short distance away, I purposely travel further down the highway, turn round and come back. My batteries last close to 5 years each. A battery "tender" is not needed unless I am traveling on vacation or work and will be gone for many weeks.

[Anchorman]

It’s a matter of understanding.  
 

The UX doesn’t have an alternator or a starter.  It has two types of battery - a big traction battery that drives the wheels and a small capacity version of the 12V battery on a conventional car.  This small one is the one causing your starting problems.  It’s only job is to power the door locks, heater  and the dashboard so it doesn’t need to be big.  That little battery gets charged by the big battery - think of it like one of those powerbanks you can carry to charge your phone and in just the same way, it needs to be connected to the big battery to work.  It is only connected when the car is in the READY mode.  If you sit in the car waiting or you keep moving it in and out of the garage, you don’t give it time to charge.  If you’re having battery problems you might take it for a drive but the only thing that helps is the time, not the distance.  You can achieve exactly the same by leaving it stood on the drive but it must be in the READY mode i.e. put your foot on the brake and press start.   It may start the engine and it may not - the computer will sort that out but you can reduce the likelihood by switching the heater off.  You can also lock the door with the second key.  If you are not using the car much, half an hour to an hour once a week will stop you having problems as long as you don’t inadvertently discharge the battery by other means. 

Edited May 10 by Anchorman

[yumseyo]

Thank you Anchorman for the detailed and useful information.  

[Tom1122]

My first experience today. Called AAA for a Jump that didn't work. Needed to call a tow to Lexus dealership.

Turns out the tow truck driver was more experienced and jumped the battery. He said with the Hybrids you have to have a Charger that is at 100% to work. He tested one he had at 50% and did not work. The one he had at 100% did the trick. The other trick he had was to push down on break and push in the start button and then immediately push down on the gas. Not happy this happened on a car with only 48K Miles but hopefully this info helps someone down the road. I was told to drive for at least a half hour and up hills to recharge the battery fully. Technology continues to make more work!

[Anchorman]

On 5/26/2023 at 2:22 AM, Tom1122 said:

My first experience today. Called AAA for a Jump that didn't work. Needed to call a tow to Lexus dealership.

Turns out the tow truck driver was more experienced and jumped the battery. He said with the Hybrids you have to have a Charger that is at 100% to work. He tested one he had at 50% and did not work. The one he had at 100% did the trick. The other trick he had was to push down on break and push in the start button and then immediately push down on the gas. Not happy this happened on a car with only 48K Miles but hopefully this info helps someone down the road. I was told to drive for at least a half hour and up hills to recharge the battery fully. Technology continues to make more work!

It’s surprising how much bad information there is on this subject.  In fact, driving for half an hour is unnecessary unless of course you need to go somewhere.   You don’t need to move an inch, just make sure you leave it READY mode for half an hour.   It’s a time function, not a distance function.  

[Mike XXX]

I decide to register this account to reply to this thread. I believe I know the root cause now.

I have a UX250h 2020 model. The same issue happens to me many times back in 2021 during winter time. I thought it was because I didn't drive it enough. Drove to the dealer performed the check and nothing suspicious. 

This year, couple days ago I experienced the same issue again after wash my car and I probably forgot to lock my car.

This time, I decide to have my car towed to the dealer (I moved to another state), and they were able to find the problem!

Google search L-SB-0036-21 DCM and checkout the pdf on the nhtsa website:

Quote

 

Some 2020 – 2021 model year ES 350, ES 300h, UX 200, and UX 250h vehicles may exhibit one or more of the following conditions:

* Depleted 12V vehicle battery when in IG-OFF.

 

My understanding is that the vehicle was sending the vehicle status to the server and to your lexus app.

This process happens too frequently when vehicle is parked and drained the 12V battery.

 

So you need to bring the car to the dealer and ask them to update the DCM firmware. I haven't got a chance to verify this solves the problem yet but I think it seems to be a reasonable root cause at least.

[Anchorman]

42 minutes ago, Mike XXX said:

I decide to register this account to reply to this thread. I believe I know the root cause now.

I have a UX250h 2020 model. The same issue happens to me many times back in 2021 during winter time. I thought it was because I didn't drive it enough. Drove to the dealer performed the check and nothing suspicious. 

This year, couple days ago I experienced the same issue again after wash my car and I probably forgot to lock my car.

This time, I decide to have my car towed to the dealer (I moved to another state), and they were able to find the problem!

Google search L-SB-0036-21 DCM and checkout the pdf on the nhtsa website:

My understanding is that the vehicle was sending the vehicle status to the server and to your lexus app.

This process happens too frequently when vehicle is parked and drained the 12V battery.

 

So you need to bring the car to the dealer and ask them to update the DCM firmware. I haven't got a chance to verify this solves the problem yet but I think it seems to be a reasonable root cause at least.

I hope it works for you but I suspect it won’t.