RastaMc

Hi guys.
Today I experience something very strange on the car. I started the beauty this afternoon to get some stuff at the supermarket. So the car started like normal, engine on!
Getting out of the garage I notice that the car went in battery mode while the motor was cold (outside temperature around the 13 degrees celsius). It was to soon to get in battery mode.
So I thought it was something normal and went out. On the high way, getting close to a traffic light, I noticed that the engine stopped running when I got my feet off the gas pedal (instantly). The temperature of the motor wasn't at the normal working temperature yet (still cold). When I got green light I pushed the pedal and the motor started to run. So I started to get my feet from the gas pedal a couple of times to see if the engine stopped running. And yes, the engine couldn't stay running. I drove for a good 30 minutes with speeds varying between 80 km/h to 150 km/h. And even at such a high speed the engine stopped running after release the gas pedal.
After doing groceries I started the car but it started directly on battery mode (after 2 hours standing there with a temperature of 13 degrees celsius while I was shopping). I noticed that both the ventilators of the motor when directly on when I pushed the power button. I wait and after the battery was consumed the motor started automatically. I checked the outside of the engine to see if I could find something suspicious but without result (even, I didn't know where to check). I drove the car and at the first corner, releasing the gas pedal, the motor stopped running again. I got the high way and did the same test, no matter what speed I got, releasing the gas pedal the motor went down.

So, does some has such an experience with this model of car? 3 weeks ago the car got a mayor maintenance (150.000 km on the counter). Lexus changed everything they normaly change at that millage. I didn't hear anything negative about the car. They did also the battery health check. Everything was OK!
I will call the Lexus dealer here in Amsterdam on monday. This is very strange to me.

Thanks for your help guys.
Cheers.

guzzy92fs

Sounds like a bad battery on my first bet, second: idle control valve, third throttle body, have you performed some cleaning to the body and cleaning the connector?

RastaMc

Thanks for the reply guzzy.

1. Bad Battery: This battery had a battery health check 3 weeks ago. I even got a certificate and 1 year warranty. Lexus said it was 100% OK. And even if this is the problem, why should the motor shot down if the battery is the problem? I would expect the battery doesn't work instead that the motor doesn't work. Or am I wrong?

2. idle control valve: do I need to have idle problems as first sign if the IACV is not working properly? The car was running last friday like new. And yesterday it suddenly started to get this problem.
And very important: is there a maintenance guide for the 450h 3rd Gen? This way I can do some small maintenance to the car, like this one.
I was searching on the forum and on the internet for a HOW TO find/clean/check the IACV on the 3rd gen 450h but I cant find anything. Any ideas?
BUT...... I found this: https://lexusenthusiast.com/2010/07/...engine-recall/
I'm specially worried about this sentence: Lexus has discovered faulty valve springs in some V8 and V6 engines in certain Lexus models sold in the U.S. Due to slight variations during the manufacturing process, some foreign material may have contaminated the valve springs resulting in potential breakage.

In such a situation, there is a remote possibility that abnormal engine noise or idling may occur. In extremely rare instances, the engine may stop while the vehicle is in operation.
In my case, I neither have any noise nor idle problems stationary.

3. Throttle body: is there a procedure how to clean this in the right way? I mean without damaging any electrical component, or making the ECU crazy (I read not to open the valve itself when cleaning, but this was on the 2nd gen GS300). Does someone have a maintenance guide?

I wil start now to check how to get to the TB itself. I hope I can have some respond before I start to dismount something I don't have to...

RastaMc

Update...

I cleaned the throttle body. It was very easy to do. I cleaned also the MAF and checked every connector I could find.
Everything seems OK to me. Everything was clean and good placed.
The car started as normally. The engine was running OK and it warmed up before it went into battery mode.
I took the car of the garage, I released the gas pedal and the motor stopped to run. Very weird.
I will wash the car now and I will call Lexus tomorrow.

guzzy92fs

Then your batteries are starting to fail, check them again with the dealer.

rl9010

Don't be alarmed if the motor shuts off if driving under 40Mph. It is normal operation of the hybrid system. If the motor were shutting off at freeway speeds then it may cause concern. I am assuming your battery level is high when the engine cuts out.

RastaMc

Morning...(here)
Yes, I know about this.
However, driving at 100 km/h (80 mph??) or even higher should not work that way. And that is my concern.
Yes, my battery level is high at that moment.

when the battery is very low the car start the engine like normal. However, if I start to drive and stop pushing the gas pedal the motor stops.

RastaMc

Hi guys.

I called Lexus today and they explained me that this is a normal behavior of the hybrid system. Really???
I own the car for 7 months right now and the system never behaved like this.
They told me to come with the car to do some inspections. However, the explanation I gave was a normal situation for the Lexus expert.