Parasitic leak - Automobile
 

My 2018 Lexus E350 was diagnosed by my mechanic as having a 1/10 th amp draw due to a parasitic leak. He pulled the fuses and relays one at a time so "they are not the problem." His opinion is that the problem is in one of the computers and recommended that I take it to the Lexus dealer.

When the car was under warranty 2 years ago, the Lexus dealer diagnosed the parasitic leak and was to have repaired it. As it has occurred again I would prefer to go to a mechanic that has the necessary equipment and experience to resolve this parasitic leak.

So I am looking for recommendations for an auto repair service to fix my problem.

The battery was dead but the car started after being charged at my home prior to taking it to my mechanic.

I had that with another brand. It was a software problem. Likely only the dealer can fix that. Check Lexus forums
online.
2018 Lexus ES 350 TSBs | CarComplaints.com

Lexus TSB LSB010817 — 2018 ES 350 | CarComplaints.com

ES - 6th Gen (2013-2018) - ClubLexus - Lexus Forum Discussion

Have you checked to see ALL of the lights are off? Try this, go out to the car at night with all of the lights off in the garage (use a flashlight), and look carefully to see if all of the lights are out. I have found: an under the hood light that remained on when the hood was closed, a glove compartment light that remained on when the door was closed, and a switch that somehow was moved to the wrong position and caused some interior lights to stay one. All these for over several years on different cars. On the newer cars some of these might be "settings" on a computer screen. With all of the computers on the newer cars, i have no idea if 100 ma is an excessive drain, I had a neighbor that found out the hard way they had to take their car out and drive it at least once every 2 weeks or end up with a dead battery. They opted of a battery tender.

Also, check the mirror lights on the visors.

Fuel tank sensor was causing a drain. Checking constantly. Needed software patch

Pulling fuses and relays is old school...voltage drop across fuses can be more productive. Fuses stay installed . There are exposed test points on both sides of the amperage number.

In the 80s, i worked on a coast wise oil tanker, and left my car in the parking lot for two weeks at a time, any time of the year.. . . Never had a problem starting a diesel car after sitting for two weeks, but no electronics were active, such as key fob sensors and security systems. Modern cars have lots of electrical monitoring devices which slowly drain the battery if not driven regularly. 4 weeks of no activity and most cars batteries will be drained sufficiently to not start the car.

I bought a battery tender, thanks to the wonderful suggestive posters on here, which works like a champ.

Many new cars, like laptops, need software updates on brand new models, and one would assume that all brand new sales have the most update software, with the latest update, etc, I would check annually if there are any software updates to your car from the manufacturer./ dealer.

Happened on my laptop, by the time i got the laptop delivered, from the order, the bios was three versions out of date.

Basically in this world, assume nothing is proper and if there is any way to cut costs, it will happen.

Of course the Alarm/Anti Theft Security system must be considered!

Trade the car in today on a fully electric one. The battery is much larger and its own parasitic draw therefore won't even be noticed. The added bonus is you'll be able to monitor the draw down in real-time on the included smart phones app.

I see we have the normal round of posts that have nothing to do with your question. I wish I was that bored!

So what you should be doing is take that information , I assume you keep your records, to a Lexus dealer like Wesley Chapel and tell them that it was just diagnosed to have the same leak, you'd like them to recheck their work.

Otherwise you're just using different tools to dig a larger hole.

Maybe A-1Exterminating.

Parasitic leak - Automobile
 

I thank all who replied and plan to take the car back to Wesley Chapel

Another thing to check is the alternator. When they go bad they can actually drain the battery

I have only had this problem once, and it was in the radio. Pull the fuse , what do you have to lose ? Lol

Parasitic leak?
 

Newer cars have a lot of "Keep alive" memory. This includes things like memory seats, preset radio stations, HVAC settings, and all the OBD and computer engine and transmission block learn knowledge. The dealer should be able to tell you based on what is the expected dormant (Not run) time that your car can set by calculating the amp hours of the battery, average temperature the car is setting and the acceptable parasitic load before the car will not start.

What is Kam memory?

Parasitic leak - Automobile
 

Thank you for your help.

Was the 1/10 th amp draw determined at the battery? If it was and you pulled all fuses and relays the draw will drop down. The ECM is fused.

The tech needs to test the load across each fuse and compare to factory spec. That should point to the problem.

After that, correcting the problem could be simple as a light switch, or involve expensive part (like radio or navigation system) replacement