Hi All. I could use some advice on a problem with my 2024 Lexus RX350h. Last week, my 2024 Lexus RX350h would not start and I was getting lots of alerts on the dash. I tried pushing the start button to turn off the car to see if that would clear the alerts. When I tried to start the car again, the "Park" light started to flash but the car would not start or respond. I was able to open the hatch to the cargo area but it would not latch again. Then I was not able to get back into the car so I had to open the door manually (who ever came up with this idea of electronic door handles should be fired!). I called AAA and they jumped the 12V battery in the cargo area by connecting their battery pack to the terminals on the battery. They did NOT enter the engine compartment under the hood. The car was then able to start again but I had 9 different warmings including check engine malfunction, All Wheel Drive System malfunction, Vehicle Stability Control System malfunction, Secondary Collision Brake System malfunction, Electronically controlled Brake System malfunction, Park Brake System malfunction, Drive Start Control malfunction, Advanced Ultrasonic Detecting Ranging System malfunction and Hybrid system malfunction. The dealer contacted Lexus engineers and they said that the ECU and two other components (don't remember the names) needed to be replaced at a minimum cost of $6.8K. Lexus will not cover this under warranty because they said it was caused by improperly jump starting the battery. They also claim that there are "teeth marks" on the Hybrid inverter in the engine compartment but AAA never went under the hood. The only folks who have done anything under the hood was the Lexus dealer for the 6 month and 1 year service.

First, why would a battery that is only 1 year and 2 months old with 6K miles fail. My speculation is that one of the components was failing and caused the battery to drain. Also, how could jumping the 12V battery in the cargo area cause all of this damage? Is this a common problem with hybrids?

The dealer has ordered the parts but Lexus has told me this is a starting point and the cost could rise based upon whether these parts fix the problems.

Once the car is repaired, I'm also concerned any future problems will be blamed on this issue and not be covered by Lexus. Should I be worried that replacing such major components is going to make the car less reliable? Would it be wise to trade this car and be done with it? I stand to lose a lot of money trading the car and would prefer not to go that route if the risks are low keeping it.

I have opened a case with Lexus HQ so I'm hoping they do the right thing and pay for these repairs. This was an expensive purchase and needless to say, I am NOT happy with Lexus and doubt I would ever buy a car from them again.

Thanks in advance for any advice you can offer.

 

Yes, caused by incorrect jump procedure. If your road side assistance was through your insurer or Lexus dealership then they would cover the cost.

 

See here
https://www.clublexus.com/forums/rx-...23-rx350h.html

 

I do not understand how jump starting the 12 volt battery could possibly damage the ECU. I've done this on my boat many times (kids <ha> leave the blower on for the night or the stereo on low) and no issue whatsoever. It is akin to simply replacing the battery.

 

These hybrid setups are very sensitive it seems.

The 12V battery in the rear starts the gas engine? I thought the hybrid had no starter motor and the hybrid battery started the gas engine through the coupler to the electric motor.

Suppose you want to put a tender on this car during a period of no usage (vacation, etc), where do you attach it? To the same locations as the jump start procedure?

 

Car and Driver just published an article on e-fuses and how they have changed the 'landscape' of automotive circuit protection. If you don't subscribe, this article might give you a glimpse of the changes.

https://chargedevs.com/features/elec...nt-protection/

I bet that using the wrong procedure will 'fry' many of those circuits!

 

Tesla has been using e-fuses for years (there is no traditional fuse box) much better solution, cheaper, faster to react and saves space.

 

Yes that was noted in the C&D article, but Tesla's don't need an ICE engine to get going, right?

 

They do need a 12V battery though.

 

Electric vehicles have much higher current circuits. ICE cars don't use e-fuses* for the simple reason that they've been building cars a certain way for decades. All the tooling, wiring, supply chain etc. is mature and reliable. Throwing all that away and starting again is very difficult and risky.

*maybe some do?

There are some traditional fuses in an electric vehicle, the battery pack for example has a giant pyro fuse. But what we're used to seeing, rows of fuses in a fuse box that isn't there in a Tesla.

 

I’ve owned two John Deere Garden tractors with advanced electronics and ECMs. You can definitely fry the ECM with a jump start. I would think the cars are even more sensitive to a sudden spike.
when necessary, I remove the battery to take it up to the house and stick it on a charger.

 

To be clear, I am referring to using the jump starter on the battery of the boat (and yes, it has an ECM - GM350). While removing the battery and charging it or replacing it is probably better, it can be pretty hard to do offshore, hence I carry a NOCO in the boat.

 

I'm just trying to associate these reports of damaged electronics with the Lexus jump-starting directions, which is to use the red contact on the fuse box, LF side of the engine bay...but connect the negative ALL THE WAY OVER on the RH side of the engine.

There must be some reason they specify that, and cause Road Service and customers to use longish jump start cables!

Please be understanding...I lived under high tension electric wires as a child.