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I don't have digital key at all but I use Homelink garage door opener. Is it possible that grage door opener located on the mirror draining the 12v battery?
Thanks for sharing your experiment. Its very valuable. I don't believe issue is in charging system as many of us using trickle charger to keep aux battery charged. I park my car in garage and a fully charged battery drains under 4 hours. This means a massive draw is happening. A fully charged 60Ah battery must take at least a week to fully discharge, hence 4 hours means something using battery badly. one reason can be week cellular signal inside garage. As I believe the car must contact Lexus remote server and weak signal means retry, retry, ... this can drain the battery very fast. Like our cellphone battery drains very fast when dealing with weak signal. when I park the car outside (where cell signal is strong), the charged battery hold itself much longer (more than 3 days that I tried so far). Two experiment can help proving this theory: a. disable remote services from app, b. install cellular signal booster inside garage. I'm going to try and share the results.
Does that make sense to you guys?
Do you use the garage door opener button on the homelink rearview mirror? Did you find that this drains the battery?
My 2024 RX450h+ was draining the 12 V battery whenever it sat for a few days. I bought a battery monitor on Amazon that tracks battery voltage and downloads data to the phone. I noticed a cyclical draining of the battery when the vehicle was off. I measured fuse voltages (vehicle off, doors latched) and found the drain was thru fuse ECU-DCC No. 3. I put a fuse extender in and monitored the current thru this fuse. (Fig. Below). Something was evidently turning on and off continuously (vehicle off) and drawing a lot of current. One of the items on this circuit is the Bluetooth Digital Key receiver assembly. (The Digital Key system uses an App on the cell phone to lock/unlock doors and even drive the vehicle without the key fob.) By chance I noticed that the cyclical discharging of the battery was triggered by the garage door opener! (See Fig. Below). It seems the Bluetooth Digital Key receiver was responding to the garage door opener, cycling on and off and discharging the battery. When I disabled the Digital Key system in the car (Settings -> Info & Security -> Enable Digital Keys -> OFF), the problem went away! I’m still able to use the Lexus App to unlock/lock the car, and see info about the vehicle (linking to it through cell phone or WiFI, I guess). But beware the Digital Key—it seems to be a source of serious parasitic battery drain.
I've not set up the digital key which, by your remarks, is a good idea. Thanks!
I've not set up the digital key which, by your remarks, is a good idea.
We still haven't been able to set up our digital key since I deleted and reinstalled the app, after trying to update the in-app Maintenance records.
I got around to calling the Technology Guy at our dealership today, and he kind of talked me out of the digital key. Understandable, since initially, it took three trips with different dealer guys to make it work!
PS, we don't lock our garaged RX, and never had a battery issue.
Do you use the garage door opener button on the homelink rearview mirror? Did you find that this drains the battery?
Just returned from extended vacation. I was driving my 2024 RX350h every day and battery maintained adequate charge, albeit too low voltage and capacity (note that this is a new battery). Returned home, parked car in garage, battery drained over night but still functioned. I fully charged the battery and monitored. It drained to 11.65V and 0% capacity in 1.5 days. I disabled the digital key as SMartin did in the origional post and fully charged the battery. After 3 days it still registers 12.19V and 30% capacity. Repeatability is reliability so I'm going to fully charge the battery, enable the digital key and see if that drains the battery as before. I'll experiment with the garage door opener variable as well.
Last edited by Lexuscome; Apr 10, 2025 at 06:23 AM.
Reason: more info
I addition to the digital key being an unreliable piece of technological garbage it now appears to be a significant parasitic battery drain. Lexus should refund anyone who has this white elephant. Most of us were stuck with it from their "allocation" method of car sales. There are probably not enough $ involved to make a class action suit viable.
Out of curiosity, are those having this issue fully connected with all the Lexus connected services? We only have the service for the app to remote start. No nav, etc.
Interesting Hyundai complaint. Yes I have Lexus navigation, safety connect, service connect, drive connect and remote connect with digital key on a 2024 RX350h premium plus if that helps. Some come with the car for 10 years and the drive connect and remote digital key expires in 3 years.
Just returned from extended vacation. I was driving my 2024 RX350h every day and battery maintained adequate charge, albeit too low voltage and capacity (note that this is a new battery). Returned home, parked car in garage, battery drained over night but still functioned. I fully charged the battery and monitored. It drained to 11.65V and 0% capacity in 1.5 days. I disabled the digital key as SMartin did in the origional post and fully charged the battery. After 3 days it still registers 12.19V and 30% capacity. Repeatability is reliability so I'm going to fully charge the battery, enable the digital key and see if that drains the battery as before. I'll experiment with the garage door opener variable as well.
I also run digital key and also have battery concerns. I'm getting 11.8v after a week of driving it at least 3 days, albeit for short distances. Originally I had attributed it to short distances not allowing it to charge, but I may have to look into the digital key issue.
My other problem was that I started it, drove it 2 hours highway (120 miles), and even at the first exit it refused to auto stop due to battery charging. So I'm thinking this battery might be dead. But the next week I exclusively drove it city, wife pulled in to hand me something before heading off and it auto stopped. Really baffling behavior.
If your car is less than 1 year old, the 12V battery is certainly still under the 4 years 50k warranty. Lexus replaced my 12v battery for the CT200 10 years ago when it was about 40k for free.
Hi guys. After the November 2024 dead battery event, last week I installed the Ionic Emergency Start battery on my 2024 RX350h. Pretty easy. As soon as I loosened the nuts on the battery the power went out. Fixed the Ionic cables, tightened everything up and put the velcro sticker on the left side of the Lexus battery. The power liftgate would not close so I did it manually. Also, the side rear view mirrors would not automatically fold. I locked the SUV and opened it up again, pressed the auto folding switch on the drivers side door and everything was back to normal. The power liftgate was working again. Also, I ran the App and could see the battery there. The Ionic users manual states that the battery bluetooth will disable in 30 days. Does this mean in 30 days I should short press the button on the red battery?
As soon as I loosened the nuts on the battery the power went out.
Does this mean in 30 days I should short press the button on the red battery?
I did not need to interrupt the 12 V battery connection to the car, by using separate nuts I bought, with which I tightened the ES to the battery/car leads on top of the the original/factory leads. This way, there always flexibility to detach the ES if one needs to, without disturbing the car's 12 V circuit with the Lexus battery - though one has to buy the couple nuts from Home Depot or similar hardware store.
The second question is already answered once in the thread: The car wakes up and resets the ES everytime it starts up to READY mode, so, as long as one starts the car at least once every 60 - 90 days, one doesn't have to do anything with the ES. If the Bluetooth connection to the phone is dead because one doesn't start the car AT ALL for 90 days, only then would one have to press the red physical button on the ES (assuming the Lexus 12 V is already dead in that situation) to activate the ES and hence start the car.
