u/Complex-Let-3029

You can see my previous post at the link
https://www.reddit.com/r/LexusRZ/s/SfYaWYa8nU

I wanted to share this update separately because I’ve heard only a few people mention the software update. After my 12V battery died, I pushed the dealer to perform a parasitic-draw test after the car sat overnight. The service manager told me Lexus engineers hadn’t actually seen the problem occurring live before and “geeked out” over finally observing it—he joked that my car is now famous. Ugh. Nice after being without it for over three weeks.

Lexus Engineering subsequently pushed an OTA software update related to the DCM/12V parasitic draw 8/13. He said it isn’t publicly available yet and may be a targeted pre-release update to specific VINs. They also replaced my 12V battery, and the dealer documented the draw dropping from ~80 mA before the update to ~30 mA afterward, which they said is normal. I was at Lexus Santa Monica in California and the service manager was very helpful.

I’ve restored my profile, app and Connected Services and am using everything normally again. Now we’ll see if it actually works—I’ll report back.

The more people that push this with Lexus dealers, the faster it goes public!

My Lexus service manager told me today that the software update for the DCM/12V battery-drain issue has finally been released and is being pushed OTA.

Given everything that’s happened, I’m cautiously skeptical until I can confirm exactly what was updated and whether it actually fixes the parasitic drain.

Has anyone received it yet? If so, are you using the Lexus app/Connected Services and your normal driver profile again, and have you had any further 12V issues?

Update: I picked up my RZ and confirmed with the service manager that Lexus Engineering pushed an OTA software update to my vehicle specifically related to the DCM/12V parasitic-draw issue. This is not a publicly available update at this point, and there’s no public version number or bulletin that I’m aware of. My assumption is that this may be a targeted engineering/pre-release update pushed to specific VINs while Lexus validates the fix.

The encouraging part: the dealer documented parasitic draw of about 80 mA before the update and 30 mA afterward, which they said is within normal range. I’ve re-enabled my profile and Connected Services and will see whether it holds under normal use.

**Update on the Lexus RZ 12V battery-drain issue: what my service manager told me**

I bought my Lexus RZ 450e about a month ago and woke up to a dead 12V battery.

The first time I brought it in, I told the service department that this appeared to match the battery-drain problem widely discussed by Lexus RZ and Toyota bZ owners on Reddit. They treated it as a routine battery issue, inspected and recharged it, and returned the car.

The battery died again one week later. I was initially told again that nothing appeared to be wrong. I insisted that they keep the car overnight, perform a parasitic-draw test, and document the results rather than simply recharge the battery again.

I have now spoken directly with the service manager, who is very aware of the issue. Here is what he told me:

* The Lexus app and vehicle may continue communicating or “pinging” each other after the car is turned off.
* In affected vehicles, that ongoing activity can drain the 12V battery.
* Repeated draining can also damage the battery itself.
* It is not affecting every vehicle, but it is more than a handful. He mentioned approximately 5,000 vehicles, although I have not independently confirmed that figure.
* Lexus engineers are reportedly working on a software update, but dealerships have not been given a release date.
* Replacing the DCM and installing a larger-capacity battery may help, but he did not consider that a permanent solution because it does not address the underlying software behavior.

The interim workaround he described is extreme: completely reset the vehicle to factory settings, stop using the Lexus app, do not establish a driver profile, and operate the car only as a guest without personalization.

He also said Lexus is offering affected customers interim resolution options through its corporate process. One option offered in my case is for Lexus to cover my car payments until the software update is released. That is the option I am pursuing.

My biggest concern is that Lexus does not appear to be proactively informing owners. Customers may be told the battery tests normally, have it recharged, and be sent home unless they know enough to keep pushing and escalate the case.

So, for anyone experiencing this:

Ask the dealer to keep the vehicle overnight and perform a documented parasitic-draw test. Contact Lexus Corporate and open a case. Ask specifically about the known app/vehicle communication issue, the pending software update, the factory-reset workaround, and what interim customer remedies are available.

Owners should not have to diagnose a new luxury vehicle through Reddit or repeatedly argue for a known issue to be taken seriously. I've opened a case with corporate and written them and the general manager of the dealership a strongly worded letter 🔥

Update on the Lexus RZ 12V battery-drain issue: what my service manager told me

I bought my Lexus RZ 450e about a month ago and woke up to a dead 12V battery.

The first time I brought it in, I told the service department that this appeared to match the battery-drain problem widely discussed by Lexus RZ and Toyota bZ owners on Reddit. They treated it as a routine battery issue, inspected and recharged it, and returned the car.

The battery died again one week later. I was initially told again that nothing appeared to be wrong. I insisted that they keep the car overnight, perform a parasitic-draw test, and document the results rather than simply recharge the battery again.

I have now spoken directly with the service manager, who is very aware of the issue. Here is what he told me:

• The Lexus app and vehicle may continue communicating or “pinging” each other after the car is turned off.
• In affected vehicles, that ongoing activity can drain the 12V battery.
• Repeated draining can also damage the battery itself.
• It is not affecting every vehicle, but it is more than a handful. He mentioned approximately 5,000 vehicles, although I have not independently confirmed that figure.
• Lexus engineers are reportedly working on a software update, but dealerships have not been given a release date.
• Replacing the DCM and installing a larger-capacity battery may help, but he did not consider that a permanent solution because it does not address the underlying software behavior.

The interim workaround he described is extreme: completely reset the vehicle to factory settings, stop using the Lexus app, do not establish a driver profile, and operate the car only as a guest without personalization.

He also said Lexus is offering affected customers interim resolution options through its corporate process. One option offered in my case is for Lexus to cover my car payments until the software update is released. That is the option I am pursuing.

My biggest concern is that Lexus does not appear to be proactively informing owners. Customers may be told the battery tests normally, have it recharged, and be sent home unless they know enough to keep pushing and escalate the case.

So, for anyone experiencing this:

Ask the dealer to keep the vehicle overnight and perform a documented parasitic-draw test. Contact Lexus Corporate and open a case. Ask specifically about the known app/vehicle communication issue, the pending software update, the factory-reset workaround, and what interim customer remedies are available.

Owners should not have to diagnose a new luxury vehicle through Reddit or repeatedly argue for a known issue to be taken seriously. I've opened a case with corporate and written them and the general manager of the dealership a strongly worded letter 🔥

Wondering if people are getting the “bumper to bumper” warranty that extends to 8 years. I was always told don’t do it but these cars are all computers. Something like over 200 screens or chips so seems like a lot could go wrong.

I'm picking up a 450e premium tomorrow. The dealer is about 100 miles aways. My first electric car. Where do I start? What do I need to know? What apps do I need to download for charging etc.? Appreciate any valuable tips!!

I am coming from a 2020 BMW 230i and debating on 350 vs 450. I like the feel of the German car but I'm looking for a more comfortable, lux drive vs the sporty feel I currently have. From what I've read, the 450 is worth the additional $$ but wondering what the practical day-to-day difference is in the way the car feels driving in the city from folks that have compared. I'm in Los Angeles.