Goodevening everyone

First of all I apologize for my eng Have mercy

For a series of coincidence a parent of mine gave me for free his lexus rx400h ( 2006 model ), I'm not familiar with hybrid cars in general but step by step I'm getting closer.
Mileage is 380k on the clock, the V6 runs incredibly fine, no leaks since the previous owner ran on the highway for the 90% of time so all the services where done every 8k/10k.

The only problem that I'm trying to troubleshooting is on the hybrid battery and in general to the hybrid system.

The symptom:
If I accelerate normally by pressing the gas pedal slowly, the car will quietly reach 160/180 kmh, but if I full kick the gas pedal the car accelerates for a few seconds and then stops, going no further.
And if I keep the gas pedal down, a lot of warning (red triangle) telling me to check hv system , vsc and abs.

For what I can tell, the HV battery is still the original one and with 380k on it and after 17 years... maybe its time is arrived? The only thing I can see is that the capacity of the charge never goes up always stay near to 50% even after 3-4 Km of downhills.

hypothesis:
I checkd with techstream for any codes and I get theese in the pic but noone seems direcly releated to a battery faliure; at this point I don't know if some ecu is bad ( like skid control, HV control, yawrate sensor ) or is the HV battery so bad that sends or mess up can signals to thoose ecus, not give the correct ammount of power in the moment of need.

If any of you have any suggestions I will be grateful!





Mirko

 

search for your error codes on the Forum
example: https://www.clublexus.com/forums/rx-...abs-light.html

Check the hybrid battery: https://www.clublexus.com/forums/rx-...l#post11120000

PS: Hybrids are here https://www.clublexus.com/forums/hybrid-technology-187/

 

Hi! Thanks and sorry for messing up with the post, but i cannot see in the section related to my model ( as you indicate ) but it's under https://www.clublexus.com/forums/hybrid-technology-274/ , should I delete the post and create a new one under https://www.clublexus.com/forums/hybrid-technology-187/ ?

 

Hi! Thanks and sorry for messing up with the post, but i cannot see in the section related to my model ( as you indicate ) but it's under https://www.clublexus.com/forums/hybrid-technology-274/ , should I delete the post and create a new one under https://www.clublexus.com/forums/hybrid-technology-187/ ?

 

It seems to me like your HV battery would be the likely problem, but that suspicion is simply based on mileage and years, not on your Techstream illustrations. My second “guess” might be the 12 volt battery. When the 12 volt battery gets weak, it can result in a variety of strange symptoms. I’m just having a hard time understanding why you would get VSC and ABS warnings if the main battery were failing. Do you know how old the 12v battery is, and would it be worth trying to replace it? Another poster already mentioned that you might get more relevant answers over in the 2nd generation subforum but I suspect you already know the answer. Prices for replacement HV drive batteries have come down here in the US but they are still expensive. Good luck with your troubleshooting. Even though this is the wrong subforum for your model year, I would love to hear back on your resolution.

 

small update: last week I went to an official lexus workshop and left the car for a diagnosis. They told me that the problem was not on the EV system but on the gas engine. They changed 6 spark plugs, 6 coils and the intake manifold gaskets but when we went to test the car, the problem was still there.

They apologized and left me a courtesy car while they delve into the problem.

I honestly don't know what to think, the 12V battery is from 2021 and the voltages seem to be in the normal range.

Anyway, I will try to post the post in the right section and see if anyone had the same problem, thank you very much

 

Hi, I’ve exactly same problem, my car is 2 months in service all ready, but they still can’t fix it, they’ve tried everything, but nothing helps. Do you solve this problem?

 

I also think it is the 12v battery. I have had quite a bit of experience with these batteries, and in all cases, the issue is solved with a new battery. For some reason those AGM batteries can test ok, but they are not ok. On my golf carts especially they can test ok, but the cart will not perform properly, until the battery is replaced.
The batteries on the hybrids are not required to crank anything, but they may be under more load when you have the throttle floored.

 

Perhaps you can find an independent shop that specializes in hybrid vehicles/batteries, and let them troubleshoot the HV battery system. Given the age of the battery, there’s a STRONG possibility that the HV battery needs to be replaced.